@alshdavid/mime-types/cjs/path/extname.js

The ultimate javascript content-type utility.

"use strict";
// Extracted from node to allow running in browser
// https://github.com/nodejs/node/blob/main/lib/path.js
Object.defineProperty(exports, "__esModule", { value: true });
exports.extname = exports.extnamePosix = exports.extnameWindows = void 0;
const isWindows = (() => {
    if (typeof process !== 'undefined') {
        return process.platform === 'win32';
    }
    return false;
})();
const Characters = Object.freeze({
    CHAR_DOT: 46,
    CHAR_COLON: 58,
    CHAR_UPPERCASE_A: 65,
    CHAR_LOWERCASE_A: 97,
    CHAR_UPPERCASE_Z: 90,
    CHAR_LOWERCASE_Z: 122,
    CHAR_FORWARD_SLASH: 47,
    CHAR_BACKWARD_SLASH: 92, /* \ */
});
function validateString(value, name) {
    if (typeof value !== 'string')
        throw new Error(`${name}, ${value} is not a string`);
}
function isWindowsDeviceRoot(code) {
    return (code >= Characters.CHAR_UPPERCASE_A && code <= Characters.CHAR_UPPERCASE_Z) ||
        (code >= Characters.CHAR_LOWERCASE_A && code <= Characters.CHAR_LOWERCASE_Z);
}
function isPathSeparator(code) {
    return code === Characters.CHAR_FORWARD_SLASH || code === Characters.CHAR_BACKWARD_SLASH;
}
function extnameWindows(path) {
    validateString(path, 'path');
    let start = 0;
    let startDot = -1;
    let startPart = 0;
    let end = -1;
    let matchedSlash = true;
    // Track the state of characters (if any) we see before our first dot and
    // after any path separator we find
    let preDotState = 0;
    // Check for a drive letter prefix so as not to mistake the following
    // path separator as an extra separator at the end of the path that can be
    // disregarded
    if (path.length >= 2 &&
        path.charCodeAt(1) === Characters.CHAR_COLON &&
        isWindowsDeviceRoot(path.charCodeAt(0))) {
        start = startPart = 2;
    }
    for (let i = path.length - 1; i >= start; --i) {
        const code = path.charCodeAt(i);
        if (isPathSeparator(code)) {
            // If we reached a path separator that was not part of a set of path
            // separators at the end of the string, stop now
            if (!matchedSlash) {
                startPart = i + 1;
                break;
            }
            continue;
        }
        if (end === -1) {
            // We saw the first non-path separator, mark this as the end of our
            // extension
            matchedSlash = false;
            end = i + 1;
        }
        if (code === Characters.CHAR_DOT) {
            // If this is our first dot, mark it as the start of our extension
            if (startDot === -1)
                startDot = i;
            else if (preDotState !== 1)
                preDotState = 1;
        }
        else if (startDot !== -1) {
            // We saw a non-dot and non-path separator before our dot, so we should
            // have a good chance at having a non-empty extension
            preDotState = -1;
        }
    }
    if (startDot === -1 ||
        end === -1 ||
        // We saw a non-dot character immediately before the dot
        preDotState === 0 ||
        // The (right-most) trimmed path component is exactly '..'
        (preDotState === 1 &&
            startDot === end - 1 &&
            startDot === startPart + 1)) {
        return '';
    }
    return path.slice(startDot, end);
}
exports.extnameWindows = extnameWindows;
function extnamePosix(path) {
    validateString(path, 'path');
    let startDot = -1;
    let startPart = 0;
    let end = -1;
    let matchedSlash = true;
    // Track the state of characters (if any) we see before our first dot and
    // after any path separator we find
    let preDotState = 0;
    for (let i = path.length - 1; i >= 0; --i) {
        const code = path.charCodeAt(i);
        if (code === Characters.CHAR_FORWARD_SLASH) {
            // If we reached a path separator that was not part of a set of path
            // separators at the end of the string, stop now
            if (!matchedSlash) {
                startPart = i + 1;
                break;
            }
            continue;
        }
        if (end === -1) {
            // We saw the first non-path separator, mark this as the end of our
            // extension
            matchedSlash = false;
            end = i + 1;
        }
        if (code === Characters.CHAR_DOT) {
            // If this is our first dot, mark it as the start of our extension
            if (startDot === -1)
                startDot = i;
            else if (preDotState !== 1)
                preDotState = 1;
        }
        else if (startDot !== -1) {
            // We saw a non-dot and non-path separator before our dot, so we should
            // have a good chance at having a non-empty extension
            preDotState = -1;
        }
    }
    if (startDot === -1 ||
        end === -1 ||
        // We saw a non-dot character immediately before the dot
        preDotState === 0 ||
        // The (right-most) trimmed path component is exactly '..'
        (preDotState === 1 &&
            startDot === end - 1 &&
            startDot === startPart + 1)) {
        return '';
    }
    return path.slice(startDot, end);
}
exports.extnamePosix = extnamePosix;
function extname(path) {
    if (isWindows) {
        return extnameWindows(path);
    }
    return extnamePosix(path);
}
exports.extname = extname;