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denoland-deno/std/datetime/formatter.ts

534 lines
14 KiB
TypeScript

import {
CallbackResult,
Rule,
TestFunction,
TestResult,
Tokenizer,
} from "./tokenizer.ts";
function digits(value: string | number, count = 2): string {
return String(value).padStart(count, "0");
}
// as declared as in namespace Intl
type 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://userguide.icu-project.org/formatparse/datetime)
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("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 };
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 }) => ({
type,
value,
})) as Format;
}
format(date: Date, options: Options = {}): string {
let string = "";
const utc = options.timeZone === "UTC";
const hour12 = this.#format.find(
(token: FormatPart) => token.type === "dayPeriod",
);
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 "${token.value}" is not supported`,
);
}
break;
}
case "hour": {
let value = utc ? date.getUTCHours() : date.getHours();
value -= hour12 && date.getHours() > 12 ? 12 : 0;
switch (token.value) {
case "numeric": {
string += value;
break;
}
case "2-digit": {
string += digits(value, 2);
break;
}
default:
throw Error(
`FormatterError: value "${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;
}
case "timeZoneName": {
// string += utc ? "Z" : token.value
// break
}
case "dayPeriod": {
string += hour12 ? (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 "${token.value}" is not supported`,
);
}
break;
}
case "hour": {
switch (token.value) {
case "numeric": {
value = /^\d{1,2}/.exec(string)?.[0] as string;
break;
}
case "2-digit": {
value = /^\d{2}/.exec(string)?.[0] as string;
break;
}
default:
throw Error(
`ParserError: value "${token.value}" is not supported`,
);
}
break;
}
case "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;
}
partsToDate(parts: DateTimeFormatPart[]): Date {
const date = new Date();
const utc = parts.find(
(part) => part.type === "timeZoneName" && part.value === "UTC",
);
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;
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);
return this.partsToDate(parts);
}
}