Built-in utilities

ArcOS comes with several utility functions built-in that may come in handy for you when you're developing your app. These functions range from array chunking to path manipulation and concatenation.

Global utilities

const Sleep: (ms?: number) => Promise<unknown>;

This function is asynchronous; it should be awaited.

Waits for ms milliseconds. That's it.

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export const Debug: (m: any) => void;

Creates a message box with m as the message.

The util object

All of these functions are properties of the util global object.

util.htmlspecialchars(text: string): string;

Makes the input HTML-safe to prevent XSS attacks.

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util.Plural: (s: string, x: number) => string;

Appends an s to the input if the x argument is 0 or above 1.

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util.sliceIntoChunks(arr: any[], chunkSize: number): any[][];

Converts an array of items into equally sized chunks.

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util.decimalToHex: (value: number, maxLength?: number) => string;

Returns a hex string representation of the input, optionally specifying a length to make the resulting string. The output will be padded with zeroes as per the maxLength parameter.

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util.sha256(message: string): Promise<string>;

This function is asynchronous; it should be awaited.

Generates an SHA256 hash for the input.

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util.CountInstances(input: string, search: string): number;

Counts how many times search is found in input.

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util.join(...args: string[]): string;

A web-based path.join implementation for joining path parts together, with support for the ArcOS Filesystem kernel module.

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util.getItemNameFromPath(path: string): string;

Returns the file or folder name from a path. For example: U:/Documents/test.txt becomes test.txt.

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util.getParentDirectory(p: string): string;

Parses the parent directory of a path. For example: U:/Applications/Minesweeper becomes U:/Applications.

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util.getDriveLetter(path: string, allowUuid?: boolean): string | undefined;

Returns the drive letter of a path. It will only allow drive UUIDs if specified. Returns undefined if the drive letter cannot be parsed.

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util.formatBytes(bytes: number): string;

Converts the input bytes to a human-readable format. Supports up to the YB size unit (excessive, I know)

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util.DownloadFile(file: ArrayBuffer, filename: string, mimetype?: string): void;

Takes an ArrayBuffer, filename and optional mimetype, and queries the browser to download that file to the user's computer.

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The following functions are of dubious reliability and should not be used regularly.

util.onFileChange(path: string, callback: () => void): void;

Watches the SystemDispatch kernel module for file changes broadcasted by the Filesystem kernel module.

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util.onFolderChange(path: string, callback: () => void): void;

Watches the SystemDispatch kernel module for folder changes broadcasted by the Filesystem kernel module.