String API

decodeURIComponentRepeatedly Decode

Repeatedly decodes a URI component until stable or the depth limit is reached.

Signature

export function decodeURIComponentRepeatedly(value: string, maxDepth = 10): string;

Example

import { decodeURIComponentRepeatedly } from "@fast-china/utils";

const result = decodeURIComponentRepeatedly("Fast 文档", 10);

Input

Input	Type	Required / default	Description
value	string	Required	Encoded component without URI path semantics.
maxDepth	unknown	Optional; defaults to 10	Maximum decoding passes; defaults to 10.

Returns

Value	Type	Description
result	string	Component text after stabilization or the limit.

parseQueryString Parse

Parses an absolute URL containing ://, a ?query, or a bare query string.

Signature

export function parseQueryString(input: string): ParsedQueryParameters;

Example

import { parseQueryString } from "@fast-china/utils";

const result = parseQueryString("?page=1&tag=vue&tag=tsx");

Input

Input	Type	Required / default	Description
input	string	Required	Full URL or query text with or without a leading question mark.

Returns

Value	Type	Description
result	ParsedQueryParameters	Repeated keys become string arrays; empty values remain empty strings.

isValidJson Validate

Checks for any valid JSON value, including scalars and null.

Signature

export function isValidJson(value: string): boolean;

Example

import { isValidJson } from "@fast-china/utils";

const result = isValidJson(`{"name":"Fast"}`);
console.log(result); // true

Input

Input	Type	Required / default	Description
value	string	Required	Text to parse; whitespace alone is not JSON.

Returns

Value	Type	Description
result	boolean	true when JSON.parse can parse the entire input.

splitWords Words

Splits words at case boundaries, hyphens, underscores, and whitespace.

Signature

export function splitWords(value: string): string[];

Example

import { splitWords } from "@fast-china/utils";

const result = splitWords("Fast 文档");

Input

Input	Type	Required / default	Description
value	string	Required	Text to split.

Returns

Value	Type	Description
result	string[]	Word array preserving input order with empty entries removed.

upperFirst Case

Uppercases the first Unicode code point.

Signature

export function upperFirst(value: string, locale?: StringLocale): string;

Example

import { upperFirst } from "@fast-china/utils";

const result = upperFirst("Fast 文档", "zh-CN");

Input

Input	Type	Required / default	Description
value	string	Required	Input text; empty strings remain empty.
locale	StringLocale	Optional	Explicit locale; fixed default en-US.

Returns

Value	Type	Description
result	string	Text after converting the first Unicode code point.

lowerFirst Case

Lowercases the first Unicode code point.

Signature

export function lowerFirst(value: string, locale?: StringLocale): string;

Example

import { lowerFirst } from "@fast-china/utils";

const result = lowerFirst("Fast 文档", "zh-CN");

Input

Input	Type	Required / default	Description
value	string	Required	Input text; empty strings remain empty.
locale	StringLocale	Optional	Explicit locale; fixed default en-US.

Returns

Value	Type	Description
result	string	Text after converting the first Unicode code point.

camelCase Camel

Converts text to camelCase.

Signature

export function camelCase(value: string, locale?: StringLocale): string;

Example

import { camelCase } from "@fast-china/utils";

const result = camelCase("Fast 文档", "zh-CN");

Input

Input	Type	Required / default	Description
value	string	Required	Text separated by case boundaries, hyphens, underscores, or whitespace.
locale	StringLocale	Optional	Case-conversion locale; fixed default en-US.

Returns

Value	Type	Description
result	string	camelCase text.

pascalCase Pascal

Converts text to PascalCase.

Signature

export function pascalCase(value: string, locale?: StringLocale): string;

Example

import { pascalCase } from "@fast-china/utils";

const result = pascalCase("Fast 文档", "zh-CN");

Input

Input	Type	Required / default	Description
value	string	Required	Uses the same argument semantics as the related case-conversion function.
locale	StringLocale	Optional	Explicit locale for case conversion.

Returns

Value	Type	Description
result	string	PascalCase text.

kebabCase Kebab

Converts text to kebab-case.

Signature

export function kebabCase(value: string, locale?: StringLocale): string;

Example

import { kebabCase } from "@fast-china/utils";

const result = kebabCase("Fast 文档", "zh-CN");

Input

Input	Type	Required / default	Description
value	string	Required	Uses the same argument semantics as the related case-conversion function.
locale	StringLocale	Optional	Explicit locale for case conversion.

Returns

Value	Type	Description
result	string	kebab-case text.

truncateGraphemes Truncate

Truncates by Unicode grapheme clusters without splitting emoji, combining marks, or surrogate pairs.

Signature

export function truncateGraphemes(value: string, maxLength: number, suffix = "…", locale?: StringLocale): string;

Example

import { truncateGraphemes } from "@fast-china/utils";

const result = truncateGraphemes("Fast 文档", 4, "…", "zh-CN");

Input

Input	Type	Required / default	Description
value	string	Required	Input text.
maxLength	number	Required	Maximum grapheme clusters to retain.
suffix	unknown	Optional; defaults to "…"	Suffix appended on truncation; defaults to … and does not count toward the limit.
locale	StringLocale	Optional	Grapheme segmentation locale; fixed default en-US.

Returns

Value	Type	Description
result	string	Original string when within the limit, otherwise truncated content plus suffix.

copy Copy

Copies text to the system clipboard.

Signature

export async function copy(value: string): Promise<void>;

Example

import { copy } from "@fast-china/utils";

const result = await copy("Fast 文档");

Input

Input	Type	Required / default	Description
value	string	Required	Text to copy.

Returns

Value	Type	Description
result	Promise<void>	Promise fulfilled after copying completes.

randomString Random

Generates a random string.

Signature

export function randomString(length: number, alphabet: string = defaultRandomAlphabet): string;

Example

import { randomString } from "@fast-china/utils";

const result = randomString(16, "ABCDEFGHJKLMNPQRSTUVWXYZ23456789");

Input

Input	Type	Required / default	Description
length	number	Required	Character count; a safe integer from 0 to 1,000,000.
alphabet	string	Optional; defaults to defaultRandomAlphabet	Must be nonempty, contain no duplicate characters, and have at most 2^32 Unicode code points.

Returns

Value	Type	Description
result	string	Random text composed of Unicode code points from alphabet.

generateUuidV4 UUID

Generates an RFC 4122 version 4 UUID.

Signature

export function generateUuidV4(): string;

Example

import { generateUuidV4 } from "@fast-china/utils";

const result = generateUuidV4();

Input

This method has no input parameters.

Returns

Value	Type	Description
result	string	Lowercase hyphenated UUID v4.

isUuidV4 UUID

Checks for an RFC 4122 version 4 UUID.

Signature

export function isUuidV4(value: string): boolean;

Example

import { isUuidV4 } from "@fast-china/utils";

const result = isUuidV4("550e8400-e29b-41d4-a716-446655440000");
console.log(result); // true

Input

Input	Type	Required / default	Description
value	string	Required	Text to validate; hexadecimal letters are case-insensitive.

Returns

Value	Type	Description
result	boolean	true when version and variant bits are correct.

escapeHtml Escape

Escapes five special characters in HTML text context.

Signature

export function escapeHtml(value: string): string;

Example

import { escapeHtml } from "@fast-china/utils";

const result = escapeHtml("Fast 文档");

Input

Input	Type	Required / default	Description
value	string	Required	String intended as HTML text-node content.

Returns

Value	Type	Description
result	string	Text with &, <, >, double quotes, and single quotes escaped.

normalizeWhitespace Whitespace

Collapses Unicode whitespace runs to one space and trims both ends.

Signature

export function normalizeWhitespace(value: string): string;

Example

import { normalizeWhitespace } from "@fast-china/utils";

const result = normalizeWhitespace("Fast 文档");

Input

Input	Type	Required / default	Description
value	string	Required	Input text.

Returns

Value	Type	Description
result	string	Normalized text; all-whitespace input becomes an empty string.