feat: String.random util

Author: medikoo

string/index.js

@@ -5,6 +5,7 @@ module.exports = {
 	"formatMethod": require("./format-method"),
 	"fromCodePoint": require("./from-code-point"),
 	"isString": require("./is-string"),
+	"random": require("./random"),
 	"randomUniq": require("./random-uniq"),
 	"raw": require("./raw")
 };

string/random.js

@@ -0,0 +1,42 @@
+"use strict";
+
+var isValue         = require("../object/is-value")
+  , toNaturalNumber = require("../number/to-pos-integer");
+
+var generated = Object.create(null), random = Math.random, uniqTryLimit = 100;
+
+var getChunk = function () {
+	return random()
+		.toString(36)
+		.slice(2);
+};
+
+var getString = function (/* length */) {
+	var str = getChunk(), length = arguments[0];
+	if (!isValue(length)) return str;
+	while (str.length < length) str += getChunk();
+	return str.slice(0, length);
+};
+
+module.exports = function (/* options */) {
+	var options = Object(arguments[0]), length = options.length, isUnique = options.isUnique;
+
+	if (isValue(length)) length = toNaturalNumber(length);
+
+	var str = getString(length);
+	if (isUnique) {
+		var count = 0;
+		while (generated[str]) {
+			if (++count === uniqTryLimit) {
+				throw new Error(
+					"Cannot generate random string.\n" +
+						"String.random is not designed to effectively generate many short and " +
+						"unique random strings"
+				);
+			}
+			str = getString(length);
+		}
+		generated[str] = true;
+	}
+	return str;
+};

test/string/random.js

@@ -0,0 +1,13 @@
+"use strict";
+
+var isValidFormat = RegExp.prototype.test.bind(/^[a-z0-9]+$/);
+
+module.exports = function (t, a) {
+	a(typeof t(), "string");
+	a.ok(t().length > 7);
+	a.not(t({ isUnique: true }), t({ isUnique: true }));
+	a.ok(isValidFormat(t()));
+	a(t({ length: 1 }).length, 1);
+	a(t({ length: 100 }).length, 100);
+	a(t({ length: 0 }), "");
+};