feat: add String.prototype.count

string/#/count.js

@@ -0,0 +1,17 @@
+'use strict';
+
+var ensureString = require('../../object/validate-stringifiable-value');
+
+module.exports = function (search) {
+	var string = ensureString(this), count = 0, index = 0;
+
+	search = ensureString(search);
+	if (!search) throw new TypeError("Search string cannot be empty");
+	while (true) {
+		index = string.indexOf(search, index);
+		if (index === -1) break;
+		++count;
+		index += search.length;
+	}
+	return count;
+};

string/#/index.js

@@ -3,6 +3,7 @@
 module.exports = {
 	'@@iterator':           require('./@@iterator'),
 	at:                     require('./at'),
+	count:                  require('./count'),
 	camelToHyphen:          require('./camel-to-hyphen'),
 	capitalize:             require('./capitalize'),
 	caseInsensitiveCompare: require('./case-insensitive-compare'),

test/string/#/count.js

@@ -0,0 +1,14 @@
+'use strict';
+
+module.exports = function (t, a) {
+	a.throws(function () {
+		t.call('', '');
+	});
+	a(t.call('x', 'x'), 1);
+	a(t.call('xx', 'x'), 2);
+	a(t.call('xxx', 'xx'), 1);
+	a(t.call('xxxx', 'xx'), 2);
+	a(t.call('xx', 'xxx'), 0);
+	a(t.call('', 'elo'), 0);
+	a(t.call('fooo', 'foofooo'), 0);
+};