shelving/util/file.js

Toolkit for using data in JavaScript.

import { RequiredError } from "../error/RequiredError.js";
/**
 * Split a filename into its base name and extension in a single pass.
 * - Extension with no leading dot, e.g. `"ts"`.
 * - Returns `undefined` for either part if the filename has no dot or starts with a dot only.
 *
 * @example `splitFileExtension("array.ts")` returns `["array", ".ts"]`
 * @example `splitFileExtension("no-ext")` returns `["no-ext", undefined]`
 * @example `splitFileExtension(".gitignore")` returns `[undefined, "gitignore"]`
 * @example `splitFileExtension(undefined)` returns `[undefined, undefined]`
 */
export function splitFileExtension(file = "") {
    if (!file)
        return [undefined, undefined];
    const i = file.lastIndexOf(".");
    if (i < 0)
        return [file, undefined];
    return [file.slice(0, i) || undefined, file.slice(i + 1) || undefined];
}
/** Get the file extension from a file path, e.g. `"md"`, or return `undefined` if the input has no extension. */
export function getFileExtension(file) {
    return splitFileExtension(file)[1];
}
/** Get the file extension from a file path e.g. `"tsx"`, or throw `RequiredError` if the input has no extension. */
export function requireFileExtension(file, caller = requireFileExtension) {
    const extension = getFileExtension(file);
    if (!extension)
        throw new RequiredError("File extension is required", { received: file, caller });
    return extension;
}