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std/datetime/_common.ts

Deno standard library
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// Copyright 2018-2024 the Deno authors. All rights reserved. MIT license.// This module is browser compatible.
export type Token = { type: string; value: string | number; index: number; [key: string]: unknown;};
export interface ReceiverResult { [name: string]: string | number | unknown;}export type CallbackResult = { type: string; value: string | number; [key: string]: unknown;};type CallbackFunction = (value: unknown) => CallbackResult;
export type TestResult = { value: unknown; length: number } | undefined;export type TestFunction = ( string: string,) => TestResult | undefined;
export interface Rule { test: TestFunction; fn: CallbackFunction;}
export class Tokenizer { rules: Rule[];
constructor(rules: Rule[] = []) { this.rules = rules; }
addRule(test: TestFunction, fn: CallbackFunction): Tokenizer { this.rules.push({ test, fn }); return this; }
tokenize( string: string, receiver = (token: Token): ReceiverResult => token, ): ReceiverResult[] { function* generator(rules: Rule[]): IterableIterator<ReceiverResult> { let index = 0; for (const rule of rules) { const result = rule.test(string); if (result) { const { value, length } = result; index += length; string = string.slice(length); const token = { ...rule.fn(value), index }; yield receiver(token); yield* generator(rules); } } } const tokenGenerator = generator(this.rules);
const tokens: ReceiverResult[] = [];
for (const token of tokenGenerator) { tokens.push(token); }
if (string.length) { throw new Error( `parser error: string not fully parsed! ${string.slice(0, 25)}`, ); }
return tokens; }}
function digits(value: string | number, count = 2): string { return String(value).padStart(count, "0");}
// as declared as in namespace Intltype DateTimeFormatPartTypes = | "day" | "dayPeriod" // | "era" | "hour" | "literal" | "minute" | "month" | "second" | "timeZoneName" // | "weekday" | "year" | "fractionalSecond";
interface DateTimeFormatPart { type: DateTimeFormatPartTypes; value: string;}
type TimeZone = "UTC";
interface Options { timeZone?: TimeZone;}
function createLiteralTestFunction(value: string): TestFunction { return (string: string): TestResult => { return string.startsWith(value) ? { value, length: value.length } : undefined; };}
function createMatchTestFunction(match: RegExp): TestFunction { return (string: string): TestResult => { const result = match.exec(string); if (result) return { value: result, length: result[0].length }; };}
// according to unicode symbols (http://www.unicode.org/reports/tr35/tr35-dates.html#Date_Field_Symbol_Table)const defaultRules = [ { test: createLiteralTestFunction("yyyy"), fn: (): CallbackResult => ({ type: "year", value: "numeric" }), }, { test: createLiteralTestFunction("yy"), fn: (): CallbackResult => ({ type: "year", value: "2-digit" }), },
{ test: createLiteralTestFunction("MM"), fn: (): CallbackResult => ({ type: "month", value: "2-digit" }), }, { test: createLiteralTestFunction("M"), fn: (): CallbackResult => ({ type: "month", value: "numeric" }), }, { test: createLiteralTestFunction("dd"), fn: (): CallbackResult => ({ type: "day", value: "2-digit" }), }, { test: createLiteralTestFunction("d"), fn: (): CallbackResult => ({ type: "day", value: "numeric" }), },
{ test: createLiteralTestFunction("HH"), fn: (): CallbackResult => ({ type: "hour", value: "2-digit" }), }, { test: createLiteralTestFunction("H"), fn: (): CallbackResult => ({ type: "hour", value: "numeric" }), }, { test: createLiteralTestFunction("hh"), fn: (): CallbackResult => ({ type: "hour", value: "2-digit", hour12: true, }), }, { test: createLiteralTestFunction("h"), fn: (): CallbackResult => ({ type: "hour", value: "numeric", hour12: true, }), }, { test: createLiteralTestFunction("mm"), fn: (): CallbackResult => ({ type: "minute", value: "2-digit" }), }, { test: createLiteralTestFunction("m"), fn: (): CallbackResult => ({ type: "minute", value: "numeric" }), }, { test: createLiteralTestFunction("ss"), fn: (): CallbackResult => ({ type: "second", value: "2-digit" }), }, { test: createLiteralTestFunction("s"), fn: (): CallbackResult => ({ type: "second", value: "numeric" }), }, { test: createLiteralTestFunction("SSS"), fn: (): CallbackResult => ({ type: "fractionalSecond", value: 3 }), }, { test: createLiteralTestFunction("SS"), fn: (): CallbackResult => ({ type: "fractionalSecond", value: 2 }), }, { test: createLiteralTestFunction("S"), fn: (): CallbackResult => ({ type: "fractionalSecond", value: 1 }), },
{ test: createLiteralTestFunction("a"), fn: (value: unknown): CallbackResult => ({ type: "dayPeriod", value: value as string, }), },
// quoted literal { test: createMatchTestFunction(/^(')(?<value>\\.|[^\']*)\1/), fn: (match: unknown): CallbackResult => ({ type: "literal", value: (match as RegExpExecArray).groups!.value as string, }), }, // literal { test: createMatchTestFunction(/^.+?\s*/), fn: (match: unknown): CallbackResult => ({ type: "literal", value: (match as RegExpExecArray)[0], }), },];
type FormatPart = { type: DateTimeFormatPartTypes; value: string | number; hour12?: boolean;};type Format = FormatPart[];
export class DateTimeFormatter { #format: Format;
constructor(formatString: string, rules: Rule[] = defaultRules) { const tokenizer = new Tokenizer(rules); this.#format = tokenizer.tokenize( formatString, ({ type, value, hour12 }) => { const result = { type, value, } as unknown as ReceiverResult; if (hour12) result.hour12 = hour12 as boolean; return result; }, ) as Format; }
format(date: Date, options: Options = {}): string { let string = "";
const utc = options.timeZone === "UTC";
for (const token of this.#format) { const type = token.type;
switch (type) { case "year": { const value = utc ? date.getUTCFullYear() : date.getFullYear(); switch (token.value) { case "numeric": { string += value; break; } case "2-digit": { string += digits(value, 2).slice(-2); break; } default: throw Error( `FormatterError: value "${token.value}" is not supported`, ); } break; } case "month": { const value = (utc ? date.getUTCMonth() : date.getMonth()) + 1; switch (token.value) { case "numeric": { string += value; break; } case "2-digit": { string += digits(value, 2); break; } default: throw Error( `FormatterError: value "${token.value}" is not supported`, ); } break; } case "day": { const value = utc ? date.getUTCDate() : date.getDate(); switch (token.value) { case "numeric": { string += value; break; } case "2-digit": { string += digits(value, 2); break; } default: throw Error( `FormatterError: value "${token.value}" is not supported`, ); } break; } case "hour": { let value = utc ? date.getUTCHours() : date.getHours(); if (token.hour12) { if (value === 0) value = 12; else if (value > 12) value -= 12; } switch (token.value) { case "numeric": { string += value; break; } case "2-digit": { string += digits(value, 2); break; } default: throw Error( `FormatterError: value "${token.value}" is not supported`, ); } break; } case "minute": { const value = utc ? date.getUTCMinutes() : date.getMinutes(); switch (token.value) { case "numeric": { string += value; break; } case "2-digit": { string += digits(value, 2); break; } default: throw Error( `FormatterError: value "${token.value}" is not supported`, ); } break; } case "second": { const value = utc ? date.getUTCSeconds() : date.getSeconds(); switch (token.value) { case "numeric": { string += value; break; } case "2-digit": { string += digits(value, 2); break; } default: throw Error( `FormatterError: value "${token.value}" is not supported`, ); } break; } case "fractionalSecond": { const value = utc ? date.getUTCMilliseconds() : date.getMilliseconds(); string += digits(value, Number(token.value)); break; } // FIXME(bartlomieju) case "timeZoneName": { // string += utc ? "Z" : token.value break; } case "dayPeriod": { string += token.value ? (date.getHours() >= 12 ? "PM" : "AM") : ""; break; } case "literal": { string += token.value; break; }
default: throw Error(`FormatterError: { ${token.type} ${token.value} }`); } }
return string; }
parseToParts(string: string): DateTimeFormatPart[] { const parts: DateTimeFormatPart[] = [];
for (const token of this.#format) { const type = token.type;
let value = ""; switch (token.type) { case "year": { switch (token.value) { case "numeric": { value = /^\d{1,4}/.exec(string)?.[0] as string; break; } case "2-digit": { value = /^\d{1,2}/.exec(string)?.[0] as string; break; } } break; } case "month": { switch (token.value) { case "numeric": { value = /^\d{1,2}/.exec(string)?.[0] as string; break; } case "2-digit": { value = /^\d{2}/.exec(string)?.[0] as string; break; } case "narrow": { value = /^[a-zA-Z]+/.exec(string)?.[0] as string; break; } case "short": { value = /^[a-zA-Z]+/.exec(string)?.[0] as string; break; } case "long": { value = /^[a-zA-Z]+/.exec(string)?.[0] as string; break; } default: throw Error( `ParserError: value "${token.value}" is not supported`, ); } break; } case "day": { switch (token.value) { case "numeric": { value = /^\d{1,2}/.exec(string)?.[0] as string; break; } case "2-digit": { value = /^\d{2}/.exec(string)?.[0] as string; break; } default: throw Error( `ParserError: value "${token.value}" is not supported`, ); } break; } case "hour": { switch (token.value) { case "numeric": { value = /^\d{1,2}/.exec(string)?.[0] as string; if (token.hour12 && parseInt(value) > 12) { console.error( `Trying to parse hour greater than 12. Use 'H' instead of 'h'.`, ); } break; } case "2-digit": { value = /^\d{2}/.exec(string)?.[0] as string; if (token.hour12 && parseInt(value) > 12) { console.error( `Trying to parse hour greater than 12. Use 'HH' instead of 'hh'.`, ); } break; } default: throw Error( `ParserError: value "${token.value}" is not supported`, ); } break; } case "minute": { switch (token.value) { case "numeric": { value = /^\d{1,2}/.exec(string)?.[0] as string; break; } case "2-digit": { value = /^\d{2}/.exec(string)?.[0] as string; break; } default: throw Error( `ParserError: value "${token.value}" is not supported`, ); } break; } case "second": { switch (token.value) { case "numeric": { value = /^\d{1,2}/.exec(string)?.[0] as string; break; } case "2-digit": { value = /^\d{2}/.exec(string)?.[0] as string; break; } default: throw Error( `ParserError: value "${token.value}" is not supported`, ); } break; } case "fractionalSecond": { value = new RegExp(`^\\d{${token.value}}`).exec(string) ?.[0] as string; break; } case "timeZoneName": { value = token.value as string; break; } case "dayPeriod": { value = /^(A|P)M/.exec(string)?.[0] as string; break; } case "literal": { if (!string.startsWith(token.value as string)) { throw Error( `Literal "${token.value}" not found "${string.slice(0, 25)}"`, ); } value = token.value as string; break; }
default: throw Error(`${token.type} ${token.value}`); }
if (!value) { throw Error( `value not valid for token { ${type} ${value} } ${ string.slice( 0, 25, ) }`, ); } parts.push({ type, value });
string = string.slice(value.length); }
if (string.length) { throw Error( `datetime string was not fully parsed! ${string.slice(0, 25)}`, ); }
return parts; }
/** sort & filter dateTimeFormatPart */ sortDateTimeFormatPart(parts: DateTimeFormatPart[]): DateTimeFormatPart[] { let result: DateTimeFormatPart[] = []; const typeArray = [ "year", "month", "day", "hour", "minute", "second", "fractionalSecond", ]; for (const type of typeArray) { const current = parts.findIndex((el) => el.type === type); if (current !== -1) { result = result.concat(parts.splice(current, 1)); } } result = result.concat(parts); return result; }
partsToDate(parts: DateTimeFormatPart[]): Date { const date = new Date(); const utc = parts.find( (part) => part.type === "timeZoneName" && part.value === "UTC", );
const dayPart = parts.find((part) => part.type === "day");
utc ? date.setUTCHours(0, 0, 0, 0) : date.setHours(0, 0, 0, 0); for (const part of parts) { switch (part.type) { case "year": { const value = Number(part.value.padStart(4, "20")); utc ? date.setUTCFullYear(value) : date.setFullYear(value); break; } case "month": { const value = Number(part.value) - 1; if (dayPart) { utc ? date.setUTCMonth(value, Number(dayPart.value)) : date.setMonth(value, Number(dayPart.value)); } else { utc ? date.setUTCMonth(value) : date.setMonth(value); } break; } case "day": { const value = Number(part.value); utc ? date.setUTCDate(value) : date.setDate(value); break; } case "hour": { let value = Number(part.value); const dayPeriod = parts.find( (part: DateTimeFormatPart) => part.type === "dayPeriod", ); if (dayPeriod?.value === "PM") value += 12; utc ? date.setUTCHours(value) : date.setHours(value); break; } case "minute": { const value = Number(part.value); utc ? date.setUTCMinutes(value) : date.setMinutes(value); break; } case "second": { const value = Number(part.value); utc ? date.setUTCSeconds(value) : date.setSeconds(value); break; } case "fractionalSecond": { const value = Number(part.value); utc ? date.setUTCMilliseconds(value) : date.setMilliseconds(value); break; } } } return date; }
parse(string: string): Date { const parts = this.parseToParts(string); const sortParts = this.sortDateTimeFormatPart(parts); return this.partsToDate(sortParts); }}