monaco-yaml/src/languageservice/utils/strings.ts

/*---------------------------------------------------------------------------------------------
 *  Copyright (c) Microsoft Corporation. All rights reserved.
 *  Licensed under the MIT License. See License.txt in the project root for license information.
 *--------------------------------------------------------------------------------------------*/
'use strict';

export function startsWith(haystack: string, needle: string): boolean {
	if (haystack.length < needle.length) {
		return false;
	}

	for (let i = 0; i < needle.length; i++) {
		if (haystack[i] !== needle[i]) {
			return false;
		}
	}

	return true;
}

/**
 * Determines if haystack ends with needle.
 */
export function endsWith(haystack: string, needle: string): boolean {
	let diff = haystack.length - needle.length;
	if (diff > 0) {
		return haystack.lastIndexOf(needle) === diff;
	} else if (diff === 0) {
		return haystack === needle;
	} else {
		return false;
	}
}

export function convertSimple2RegExp(pattern: string): RegExp {
	var match = pattern.match(new RegExp('^/(.*?)/([gimy]*)$'));
	return match ? convertRegexString2RegExp(match[1], match[2])
		:  convertGlobalPattern2RegExp(pattern)
}

function convertGlobalPattern2RegExp(pattern: string): RegExp {
	return new RegExp(pattern.replace(/[\-\\\{\}\+\?\|\^\$\.\,\[\]\(\)\#\s]/g, '\\$&').replace(/[\*]/g, '.*') + '$');
}

function convertRegexString2RegExp(pattern: string, flag: string): RegExp {
	return new RegExp(pattern, flag);
}