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var R = require('../source');var eq = require('./shared/eq');

describe('bind', function() {
  function Foo(x) {    this.x = x;  }  function add(x) {    return this.x + x;  }  function Bar(x, y) {    this.x = x;    this.y = y;  }  Bar.prototype = new Foo();  Bar.prototype.getX = function() {    return 'prototype getX';  };
  it('returns a function', function() {    eq(typeof R.bind(add, Foo), 'function');  });
  it('returns a function bound to the specified context object', function() {    var f = new Foo(12);    function isFoo() {      return this instanceof Foo;    }    var isFooBound = R.bind(isFoo, f);    eq(isFoo(), false);    eq(isFooBound(), true);  });
  it('works with built-in types', function() {    var abc = R.bind(String.prototype.toLowerCase, 'ABCDEFG');    eq(typeof abc, 'function');    eq(abc(), 'abcdefg');  });
  it('works with user-defined types', function() {    var f = new Foo(12);    function getX() {      return this.x;    }    var getXFooBound = R.bind(getX, f);    eq(getXFooBound(), 12);  });
  it('works with plain objects', function() {    var pojso = {      x: 100    };    function incThis() {      return this.x + 1;    }    var incPojso = R.bind(incThis, pojso);    eq(typeof incPojso, 'function');    eq(incPojso(), 101);  });
  it('does not interfere with existing object methods', function() {    var b = new Bar('a', 'b');    function getX() {      return this.x;    }    var getXBarBound = R.bind(getX, b);    eq(b.getX(), 'prototype getX');    eq(getXBarBound(), 'a');  });
  it('preserves arity', function() {    var f0 = function() { return 0; };    var f1 = function(a) { return a; };    var f2 = function(a, b) { return a + b; };    var f3 = function(a, b, c) { return a + b + c; };
    eq(R.bind(f0, {}).length, 0);    eq(R.bind(f1, {}).length, 1);    eq(R.bind(f2, {}).length, 2);    eq(R.bind(f3, {}).length, 3);  });
});