A special placeholder value used to specify "gaps" within curried functions, allowing partial application of any combination of arguments, regardless of their positions.

Adds two values.

Creates a new list iteration function from an existing one by adding two new parameters to its callback function: the current index, and the entire list.

Applies a function to the value at the given index of an array, returning a new copy of the array with the element at the given index replaced with the result of the function application.

Returns true if all elements of the list match the predicate, false if there are any that don't.

Takes a list of predicates and returns a predicate that returns true for a given list of arguments if every one of the provided predicates is satisfied by those arguments.

Returns a function that always returns the given value. Note that for non-primitives the value returned is a reference to the original value.

Returns true if both arguments are true; false otherwise.

Returns the result of applying the onSuccess function to the value inside a successfully resolved promise. This is useful for working with promises inside function compositions.

Returns true if at least one of the elements of the list match the predicate, false otherwise.

Takes a list of predicates and returns a predicate that returns true for a given list of arguments if at least one of the provided predicates is satisfied by those arguments.

ap applies a list of functions to a list of values.

Returns a new list, composed of n-tuples of consecutive elements. If n is greater than the length of the list, an empty list is returned.

Returns a new list containing the contents of the given list, followed by the given element.

Applies function fn to the argument list args. This is useful for creating a fixed-arity function from a variadic function. fn should be a bound function if context is significant.

Given a spec object recursively mapping properties to functions, creates a function producing an object of the same structure, by mapping each property to the result of calling its associated function with the supplied arguments.

Takes a value and applies a function to it.

Makes an ascending comparator function out of a function that returns a value that can be compared with < and >.

Makes a shallow clone of an object, setting or overriding the specified property with the given value. Note that this copies and flattens prototype properties onto the new object as well. All non-primitive properties are copied by reference.

Makes a shallow clone of an object, setting or overriding the nodes required to create the given path, and placing the specific value at the tail end of that path. Note that this copies and flattens prototype properties onto the new object as well. All non-primitive properties are copied by reference.

Wraps a function of any arity (including nullary) in a function that accepts exactly 2 parameters. Any extraneous parameters will not be passed to the supplied function.

Creates a function that is bound to a context. Note: R.bind does not provide the additional argument-binding capabilities of Function.prototype.bind.

A function which calls the two provided functions and returns the && of the results. It returns the result of the first function if it is false-y and the result of the second function otherwise. Note that this is short-circuited, meaning that the second function will not be invoked if the first returns a false-y value.

Returns the result of calling its first argument with the remaining arguments. This is occasionally useful as a converging function for R.converge: the first branch can produce a function while the remaining branches produce values to be passed to that function as its arguments.

chain maps a function over a list and concatenates the results. chain is also known as flatMap in some libraries.

Restricts a number to be within a range.

Creates a deep copy of the source that can be used in place of the source object without retaining any references to it. The source object may contain (nested) Arrays and Objects, Numbers, Strings, Booleans and Dates. Functions are assigned by reference rather than copied.

Splits a list into sub-lists, based on the result of calling a key-returning function on each element, and grouping the results according to values returned.

Makes a comparator function out of a function that reports whether the first element is less than the second.

Takes a function f and returns a function g such that if called with the same arguments when f returns a "truthy" value, g returns false and when f returns a "falsy" value g returns true.

Performs right-to-left function composition using transforming function. The last function may have any arity; the remaining functions must be unary.

Returns the result of concatenating the given lists or strings.

Returns a function, fn, which encapsulates if/else, if/else, ... logic. R.cond takes a list of [predicate, transformer] pairs. All of the arguments to fn are applied to each of the predicates in turn until one returns a "truthy" value, at which point fn returns the result of applying its arguments to the corresponding transformer. If none of the predicates matches, fn returns undefined.

Wraps a constructor function inside a curried function that can be called with the same arguments and returns the same type.

Wraps a constructor function inside a curried function that can be called with the same arguments and returns the same type. The arity of the function returned is specified to allow using variadic constructor functions.

Accepts a converging function and a list of branching functions and returns a new function. The arity of the new function is the same as the arity of the longest branching function. When invoked, this new function is applied to some arguments, and each branching function is applied to those same arguments. The results of each branching function are passed as arguments to the converging function to produce the return value.

Counts the elements of a list according to how many match each value of a key generated by the supplied function. Returns an object mapping the keys produced by fn to the number of occurrences in the list. Note that all keys are coerced to strings because of how JavaScript objects work.

Returns a curried equivalent of the provided function. The curried function has two unusual capabilities. First, its arguments needn't be provided one at a time. If f is a ternary function and g is R.curry(f), the following are equivalent:

Returns a curried equivalent of the provided function, with the specified arity. The curried function has two unusual capabilities. First, its arguments needn't be provided one at a time. If g is R.curryN(3, f), the following are equivalent:

Decrements its argument.

Returns the second argument if it is not null, undefined or NaN; otherwise the first argument is returned.

Makes a descending comparator function out of a function that returns a value that can be compared with < and >.

Finds the set (i.e. no duplicates) of all elements in the first list not contained in the second list. Objects and Arrays are compared in terms of value equality, not reference equality.

Finds the set (i.e. no duplicates) of all elements in the first list not contained in the second list. Duplication is determined according to the value returned by applying the supplied predicate to two list elements.

Returns a new object that does not contain a prop property.

Makes a shallow clone of an object, omitting the property at the given path. Note that this copies and flattens prototype properties onto the new object as well. All non-primitive properties are copied by reference.

Divides two numbers. Equivalent to a / b.

Returns all but the first n elements of the given list, string, or transducer/transformer (or object with a drop method).

Returns a list containing all but the last n elements of the given list.

Returns a new list excluding all the tailing elements of a given list which satisfy the supplied predicate function. It passes each value from the right to the supplied predicate function, skipping elements until the predicate function returns a falsy value. The predicate function is applied to one argument: (value).

Returns a new list without any consecutively repeating elements. R.equals is used to determine equality.

Returns a new list without any consecutively repeating elements. Equality is determined by applying the supplied predicate to each pair of consecutive elements. The first element in a series of equal elements will be preserved.

Returns a new list excluding the leading elements of a given list which satisfy the supplied predicate function. It passes each value to the supplied predicate function, skipping elements while the predicate function returns true. The predicate function is applied to one argument: (value).

A function wrapping calls to the two functions in an || operation, returning the result of the first function if it is truth-y and the result of the second function otherwise. Note that this is short-circuited, meaning that the second function will not be invoked if the first returns a truth-y value.

Returns the empty value of its argument's type. Ramda defines the empty value of Array ([]), Object ({}), String (''), TypedArray (Uint8Array [], Float32Array [], etc), and Arguments. Other types are supported if they define <Type>.empty, <Type>.prototype.empty or implement the FantasyLand Monoid spec.

Checks if a list ends with the provided sublist.

Takes a function and two values in its domain and returns true if the values map to the same value in the codomain; false otherwise.

Reports whether two objects have the same value, in R.equals terms, for the specified property. Useful as a curried predicate.

Returns true if its arguments are equivalent, false otherwise. Handles cyclical data structures.

Creates a new object by recursively evolving a shallow copy of object, according to the transformation functions. All non-primitive properties are copied by reference.

A function that always returns false. Any passed in parameters are ignored.

Takes a predicate and a Filterable, and returns a new filterable of the same type containing the members of the given filterable which satisfy the given predicate. Filterable objects include plain objects or any object that has a filter method such as Array.

Returns the first element of the list which matches the predicate, or undefined if no element matches.

Returns the index of the first element of the list which matches the predicate, or -1 if no element matches.

Returns the last element of the list which matches the predicate, or undefined if no element matches.

Returns the index of the last element of the list which matches the predicate, or -1 if no element matches.

Returns a new list by pulling every item out of it (and all its sub-arrays) and putting them in a new array, depth-first.

Returns a new function much like the supplied one, except that the first two arguments' order is reversed.

Iterate over an input list, calling a provided function fn for each element in the list.

Iterate over an input object, calling a provided function fn for each key and value in the object.

Creates a new object from a list key-value pairs. If a key appears in multiple pairs, the rightmost pair is included in the object.

Splits a list into sub-lists stored in an object, based on the result of calling a key-returning function on each element, and grouping the results according to values returned.

Takes a list and returns a list of lists where each sublist's elements are all satisfied pairwise comparison according to the provided function. Only adjacent elements are passed to the comparison function.

Returns true if the first argument is greater than the second; false otherwise.

Returns true if the first argument is greater than or equal to the second; false otherwise.

Returns whether or not an object has an own property with the specified name

Returns whether or not an object or its prototype chain has a property with the specified name

Returns whether or not a path exists in an object. Only the object's own properties are checked.

Returns the first element of the given list or string. In some libraries this function is named first.

Returns true if its arguments are identical, false otherwise. Values are identical if they reference the same memory. NaN is identical to NaN; 0 and -0 are not identical.

A function that does nothing but return the parameter supplied to it. Good as a default or placeholder function.

Creates a function that will process either the onTrue or the onFalse function depending upon the result of the condition predicate.

Increments its argument.

Returns true if the specified value is equal, in R.equals terms, to at least one element of the given list; false otherwise. Also works with strings.

Given a function that generates a key, turns a list of objects into an object indexing the objects by the given key. Note that if multiple objects generate the same value for the indexing key only the last value will be included in the generated object.

Returns the position of the first occurrence of an item in an array, or -1 if the item is not included in the array. R.equals is used to determine equality.

Returns all but the last element of the given list or string.

Takes a predicate pred, a list xs, and a list ys, and returns a list xs' comprising each of the elements of xs which is equal to one or more elements of ys according to pred.

Inserts the supplied element into the list, at the specified index. _Note that

Inserts the sub-list into the list, at the specified index. Note that this is not destructive: it returns a copy of the list with the changes. No lists have been harmed in the application of this function.

Combines two lists into a set (i.e. no duplicates) composed of those elements common to both lists.

Creates a new list with the separator interposed between elements.

Transforms the items of the list with the transducer and appends the transformed items to the accumulator using an appropriate iterator function based on the accumulator type.

Same as R.invertObj, however this accounts for objects with duplicate values by putting the values into an array.

Returns a new object with the keys of the given object as values, and the values of the given object, which are coerced to strings, as keys. Note that the last key found is preferred when handling the same value.

Turns a named method with a specified arity into a function that can be called directly supplied with arguments and a target object.

See if an object (val) is an instance of the supplied constructor. This function will check up the inheritance chain, if any.

Returns true if the given value is its type's empty value; false otherwise.

Checks if the input value is null or undefined.

Returns a string made by inserting the separator between each element and concatenating all the elements into a single string.

juxt applies a list of functions to a list of values.

Returns a list containing the names of all the enumerable own properties of the supplied object. Note that the order of the output array is not guaranteed to be consistent across different JS platforms.

Returns a list containing the names of all the properties of the supplied object, including prototype properties. Note that the order of the output array is not guaranteed to be consistent across different JS platforms.

Returns the last element of the given list or string.

Returns the position of the last occurrence of an item in an array, or -1 if the item is not included in the array. R.equals is used to determine equality.

Returns the number of elements in the array by returning list.length.

Returns a lens for the given getter and setter functions. The getter "gets" the value of the focus; the setter "sets" the value of the focus. The setter should not mutate the data structure.

Returns a lens whose focus is the specified index.

Returns a lens whose focus is the specified path.

Returns a lens whose focus is the specified property.

"lifts" a function of arity > 1 so that it may "map over" a list, Function or other object that satisfies the FantasyLand Apply spec.

"lifts" a function to be the specified arity, so that it may "map over" that many lists, Functions or other objects that satisfy the FantasyLand Apply spec.

Returns true if the first argument is less than the second; false otherwise.

Returns true if the first argument is less than or equal to the second; false otherwise.

Takes a function and a functor, applies the function to each of the functor's values, and returns a functor of the same shape.

The mapAccum function behaves like a combination of map and reduce; it applies a function to each element of a list, passing an accumulating parameter from left to right, and returning a final value of this accumulator together with the new list.

The mapAccumRight function behaves like a combination of map and reduce; it applies a function to each element of a list, passing an accumulating parameter from right to left, and returning a final value of this accumulator together with the new list.

An Object-specific version of map. The function is applied to three arguments: (value, key, obj). If only the value is significant, use map instead.

Tests a regular expression against a String. Note that this function will return an empty array when there are no matches. This differs from String.prototype.match which returns null when there are no matches.

mathMod behaves like the modulo operator should mathematically, unlike the % operator (and by extension, R.modulo). So while -17 % 5 is -2, mathMod(-17, 5) is 3. mathMod requires Integer arguments, and returns NaN when the modulus is zero or negative.

Returns the larger of its two arguments.

Takes a function and two values, and returns whichever value produces the larger result when passed to the provided function.

Returns the mean of the given list of numbers.

Returns the median of the given list of numbers.

Creates a new function that, when invoked, caches the result of calling fn for a given argument set and returns the result. Subsequent calls to the memoized fn with the same argument set will not result in an additional call to fn; instead, the cached result for that set of arguments will be returned.

Creates one new object with the own properties from a list of objects. If a key exists in more than one object, the value from the last object it exists in will be used.

Creates a new object with the own properties of the first object merged with the own properties of the second object. If a key exists in both objects:

• and both values are objects, the two values will be recursively merged
• otherwise the value from the first object will be used.

Creates a new object with the own properties of the first object merged with the own properties of the second object. If a key exists in both objects:

• and both values are objects, the two values will be recursively merged
• otherwise the value from the second object will be used.

Creates a new object with the own properties of the two provided objects. If a key exists in both objects:

• and both associated values are also objects then the values will be recursively merged.
• otherwise the provided function is applied to associated values using the resulting value as the new value associated with the key. If a key only exists in one object, the value will be associated with the key of the resulting object.

Creates a new object with the own properties of the two provided objects. If a key exists in both objects:

• and both associated values are also objects then the values will be recursively merged.
• otherwise the provided function is applied to the key and associated values using the resulting value as the new value associated with the key. If a key only exists in one object, the value will be associated with the key of the resulting object.

Create a new object with the own properties of the first object merged with the own properties of the second object. If a key exists in both objects, the value from the first object will be used.

Create a new object with the own properties of the first object merged with the own properties of the second object. If a key exists in both objects, the value from the second object will be used.

Creates a new object with the own properties of the two provided objects. If a key exists in both objects, the provided function is applied to the values associated with the key in each object, with the result being used as the value associated with the key in the returned object.

Creates a new object with the own properties of the two provided objects. If a key exists in both objects, the provided function is applied to the key and the values associated with the key in each object, with the result being used as the value associated with the key in the returned object.

Returns the smaller of its two arguments.

Takes a function and two values, and returns whichever value produces the smaller result when passed to the provided function.

Creates a copy of the passed object by applying an fn function to the given prop property.

Creates a shallow clone of the passed object by applying an fn function to the value at the given path.

Divides the first parameter by the second and returns the remainder. Note that this function preserves the JavaScript-style behavior for modulo. For mathematical modulo see mathMod.

Move an item, at index from, to index to, in a list of elements. A new list will be created containing the new elements order.

Multiplies two numbers. Equivalent to a * b but curried.

Wraps a function of any arity (including nullary) in a function that accepts exactly n parameters. Any extraneous parameters will not be passed to the supplied function.

Negates its argument.

Returns true if no elements of the list match the predicate, false otherwise.

A function that returns the ! of its argument. It will return true when passed false-y value, and false when passed a truth-y one.

Returns the nth element of the given list or string. If n is negative the element at index length + n is returned.

Returns a function which returns its nth argument.

o is a curried composition function that returns a unary function. Like compose, o performs right-to-left function composition. Unlike compose, the rightmost function passed to o will be invoked with only one argument. Also, unlike compose, o is limited to accepting only 2 unary functions. The name o was chosen because of its similarity to the mathematical composition operator ∘.

Creates an object containing a single key:value pair.

Returns a singleton array containing the value provided.

Returns a partial copy of an object omitting the keys specified.

Takes a binary function f, a unary function g, and two values. Applies g to each value, then applies the result of each to f.

Accepts a function fn and returns a function that guards invocation of fn such that fn can only ever be called once, no matter how many times the returned function is invoked. The first value calculated is returned in subsequent invocations.

Returns true if one or both of its arguments are true. Returns false if both arguments are false.

Returns the result of applying the onFailure function to the value inside a failed promise. This is useful for handling rejected promises inside function compositions.

Returns the result of "setting" the portion of the given data structure focused by the given lens to the result of applying the given function to the focused value.

Takes two arguments, fst and snd, and returns [fst, snd].

Takes a function f and a list of arguments, and returns a function g. When applied, g returns the result of applying f to the arguments provided initially followed by the arguments provided to g.

Takes a function f and an object, and returns a function g. When applied, g returns the result of applying f to the object provided initially merged deeply (right) with the object provided as an argument to g.

Takes a function f and a list of arguments, and returns a function g. When applied, g returns the result of applying f to the arguments provided to g followed by the arguments provided initially.

Takes a predicate and a list or other Filterable object and returns the pair of filterable objects of the same type of elements which do and do not satisfy, the predicate, respectively. Filterable objects include plain objects or any object that has a filter method such as Array.

Retrieve the value at a given path.

Determines whether a nested path on an object has a specific value, in R.equals terms. Most likely used to filter a list.

If the given, non-null object has a value at the given path, returns the value at that path. Otherwise returns the provided default value.

Retrieves the values at given paths of an object.

Returns true if the specified object property at given path satisfies the given predicate; false otherwise.

Returns a partial copy of an object containing only the keys specified. If the key does not exist, the property is ignored.

Similar to pick except that this one includes a key: undefined pair for properties that don't exist.

Returns a partial copy of an object containing only the keys that satisfy the supplied predicate.

Performs left-to-right function composition using transforming function. The first function may have any arity; the remaining functions must be unary.

Returns a new list by plucking the same named property off all objects in the list supplied.

Returns a new list with the given element at the front, followed by the contents of the list.

Multiplies together all the elements of a list.

Reasonable analog to SQL select statement.

Takes two functions as pre- and post- processors respectively for a third function, i.e. promap(f, g, h)(x) === g(h(f(x))).

Returns a function that when supplied an object returns the indicated property of that object, if it exists.

Returns true if the specified object property is equal, in R.equals terms, to the given value; false otherwise. You can test multiple properties with R.whereEq.

Returns true if the specified object property is of the given type; false otherwise.

Return the specified property of the given non-null object if the property is present and it's value is not null, undefined or NaN.

Acts as multiple prop: array of keys in, array of values out. Preserves order.

Returns true if the specified object property satisfies the given predicate; false otherwise. You can test multiple properties with R.where.

Returns a list of numbers from from (inclusive) to to (exclusive).

Returns a single item by iterating through the list, successively calling the iterator function and passing it an accumulator value and the current value from the array, and then passing the result to the next call.

Groups the elements of the list according to the result of calling the String-returning function keyFn on each element and reduces the elements of each group to a single value via the reducer function valueFn.

Returns a value wrapped to indicate that it is the final value of the reduce and transduce functions. The returned value should be considered a black box: the internal structure is not guaranteed to be stable.

Returns a single item by iterating through the list, successively calling the iterator function and passing it an accumulator value and the current value from the array, and then passing the result to the next call.

Like reduce, reduceWhile returns a single item by iterating through the list, successively calling the iterator function. reduceWhile also takes a predicate that is evaluated before each step. If the predicate returns false, it "short-circuits" the iteration and returns the current value of the accumulator.

The complement of filter.

Removes the sub-list of list starting at index start and containing count elements. Note that this is not destructive: it returns a copy of the list with the changes. No lists have been harmed in the application of this function.

Returns a fixed list of size n containing a specified identical value.

Replace a substring or regex match in a string with a replacement.

Returns a new list or string with the elements or characters in reverse order.

Scan is similar to reduce, but returns a list of successively reduced values from the left

Transforms a Traversable of Applicative into an Applicative of Traversable.

Returns the result of "setting" the portion of the given data structure focused by the given lens to the given value.

Returns the elements of the given list or string (or object with a slice method) from fromIndex (inclusive) to toIndex (exclusive).

Returns a copy of the list, sorted according to the comparator function, which should accept two values at a time and return a negative number if the first value is smaller, a positive number if it's larger, and zero if they are equal. Please note that this is a copy of the list. It does not modify the original.

Sorts the list according to the supplied function.

Sorts a list according to a list of comparators.

Splits a string into an array of strings based on the given separator.

Splits a given list or string at a given index.

Splits a collection into slices of the specified length.

Takes a list and a predicate and returns a pair of lists with the following properties:

Splits an array into slices on every occurrence of a value.

Checks if a list starts with the provided sublist.

Subtracts its second argument from its first argument.

Adds together all the elements of a list.

Finds the set (i.e. no duplicates) of all elements contained in the first or second list, but not both.

Finds the set (i.e. no duplicates) of all elements contained in the first or second list, but not both. Duplication is determined according to the value returned by applying the supplied predicate to two list elements.

A function that always returns true. Any passed in parameters are ignored.

Returns all but the first element of the given list or string (or object with a tail method).

Returns the first n elements of the given list, string, or transducer/transformer (or object with a take method).

Returns a new list containing the last n elements of the given list. If n > list.length, returns a list of list.length elements.

Returns a new list containing the last n elements of a given list, passing each value to the supplied predicate function, and terminating when the predicate function returns false. Excludes the element that caused the predicate function to fail. The predicate function is passed one argument: (value).

Returns a new list containing the first n elements of a given list, passing each value to the supplied predicate function, and terminating when the predicate function returns false. Excludes the element that caused the predicate function to fail. The predicate function is passed one argument: (value).

Runs the given function with the supplied object, then returns the object.

Determines whether a given string matches a given regular expression.

Creates a thunk out of a function. A thunk delays a calculation until its result is needed, providing lazy evaluation of arguments.

Calls an input function n times, returning an array containing the results of those function calls.

The lower case version of a string.

Converts an object into an array of key, value arrays. Only the object's own properties are used. Note that the order of the output array is not guaranteed to be consistent across different JS platforms.

Converts an object into an array of key, value arrays. The object's own properties and prototype properties are used. Note that the order of the output array is not guaranteed to be consistent across different JS platforms.

Returns the string representation of the given value. eval'ing the output should result in a value equivalent to the input value. Many of the built-in toString methods do not satisfy this requirement.

The upper case version of a string.

Initializes a transducer using supplied iterator function. Returns a single item by iterating through the list, successively calling the transformed iterator function and passing it an accumulator value and the current value from the array, and then passing the result to the next call.

Transposes the rows and columns of a 2D list. When passed a list of n lists of length x, returns a list of x lists of length n.

Maps an Applicative-returning function over a Traversable, then uses sequence to transform the resulting Traversable of Applicative into an Applicative of Traversable.

Removes (strips) whitespace from both ends of the string.

tryCatch takes two functions, a tryer and a catcher. The returned function evaluates the tryer; if it does not throw, it simply returns the result. If the tryer does throw, the returned function evaluates the catcher function and returns its result. Note that for effective composition with this function, both the tryer and catcher functions must return the same type of results.

Gives a single-word string description of the (native) type of a value, returning such answers as 'Object', 'Number', 'Array', or 'Null'. Does not attempt to distinguish user Object types any further, reporting them all as 'Object'.

Takes a function fn, which takes a single array argument, and returns a function which:

Wraps a function of any arity (including nullary) in a function that accepts exactly 1 parameter. Any extraneous parameters will not be passed to the supplied function.

Returns a function of arity n from a (manually) curried function. Note that, the returned function is actually a ramda style curryied function, which can accept one or more arguments in each function calling.

Builds a list from a seed value. Accepts an iterator function, which returns either false to stop iteration or an array of length 2 containing the value to add to the resulting list and the seed to be used in the next call to the iterator function.

Combines two lists into a set (i.e. no duplicates) composed of the elements of each list.

Combines two lists into a set (i.e. no duplicates) composed of the elements of each list. Duplication is determined according to the value returned by applying the supplied predicate to two list elements. If an element exists in both lists, the first element from the first list will be used.

Returns a new list containing only one copy of each element in the original list. R.equals is used to determine equality.

Returns a new list containing only one copy of each element in the original list, based upon the value returned by applying the supplied function to each list element. Prefers the first item if the supplied function produces the same value on two items. R.equals is used for comparison.

Returns a new list containing only one copy of each element in the original list, based upon the value returned by applying the supplied predicate to two list elements. Prefers the first item if two items compare equal based on the predicate.

Tests the final argument by passing it to the given predicate function. If the predicate is not satisfied, the function will return the result of calling the whenFalseFn function with the same argument. If the predicate is satisfied, the argument is returned as is.

Shorthand for R.chain(R.identity), which removes one level of nesting from any Chain.

Takes a predicate, a transformation function, and an initial value, and returns a value of the same type as the initial value. It does so by applying the transformation until the predicate is satisfied, at which point it returns the satisfactory value.

Returns a new copy of the array with the element at the provided index replaced with the given value.

Accepts a function fn and a list of transformer functions and returns a new curried function. When the new function is invoked, it calls the function fn with parameters consisting of the result of calling each supplied handler on successive arguments to the new function.

Returns a list of all the enumerable own properties of the supplied object. Note that the order of the output array is not guaranteed across different JS platforms.

Returns a list of all the properties, including prototype properties, of the supplied object. Note that the order of the output array is not guaranteed to be consistent across different JS platforms.

Returns a "view" of the given data structure, determined by the given lens. The lens's focus determines which portion of the data structure is visible.

Tests the final argument by passing it to the given predicate function. If the predicate is satisfied, the function will return the result of calling the whenTrueFn function with the same argument. If the predicate is not satisfied, the argument is returned as is.

Takes a spec object and a test object; returns true if the test satisfies the spec. Each of the spec's own properties must be a predicate function. Each predicate is applied to the value of the corresponding property of the test object. where returns true if all the predicates return true, false otherwise.

Takes a spec object and a test object; each of the spec's own properties must be a predicate function. Each predicate is applied to the value of the corresponding property of the test object. whereAny returns true if at least one of the predicates return true, false otherwise.

Takes a spec object and a test object; returns true if the test satisfies the spec, false otherwise. An object satisfies the spec if, for each of the spec's own properties, accessing that property of the object gives the same value (in R.equals terms) as accessing that property of the spec.

Returns a new list without values in the first argument. R.equals is used to determine equality.

Exclusive disjunction logical operation. Returns true if one of the arguments is truthy and the other is falsy. Otherwise, it returns false.

Creates a new list out of the two supplied by creating each possible pair from the lists.

Creates a new list out of the two supplied by pairing up equally-positioned items from both lists. The returned list is truncated to the length of the shorter of the two input lists. Note: zip is equivalent to zipWith(function(a, b) { return [a, b] }).

Creates a new object out of a list of keys and a list of values. Key/value pairing is truncated to the length of the shorter of the two lists. Note: zipObj is equivalent to pipe(zip, fromPairs).

Creates a new list out of the two supplied by applying the function to each equally-positioned pair in the lists. The returned list is truncated to the length of the shorter of the two input lists.

Performs right-to-left function composition. The last argument may have any arity; the remaining arguments must be unary.

Performs left-to-right function composition. The first argument may have any arity; the remaining arguments must be unary.