The Symbol.match, Symbol.replace, Symbol.search, and Symbol.split Properties

Symbols.js

// effectively equivalent to /^.{10}$/
let hasLengthOf10 = {
 [Symbol.match]: function(value) {
 return value.length === 10 ? [value.substring(0, 10)] : null;
 },
 [Symbol.replace]: function(value, replacement) {
 return value.length === 10 ? replacement + value.substring(10) : value;
 },
 [Symbol.search]: function(value) {
 return value.length === 10 ? 0 : -1;
 },
 [Symbol.split]: function(value) {
 return value.length === 10 ? ["", ""] : [value];
 }
};
let message1 = "Hello world", // 11 characters
 message2 = "Hello John"; // 10 characters
let match1 = message1.match(hasLengthOf10),
 match2 = message2.match(hasLengthOf10);
console.log(match1); // null
console.log(match2); // ["Hello John"]
let replace1 = message1.replace(hasLengthOf10),
 replace2 = message2.replace(hasLengthOf10);
console.log(replace1); // "Hello world"
console.log(replace2); // "Hello John"
let search1 = message1.search(hasLengthOf10),
 search2 = message2.search(hasLengthOf10);
console.log(search1); // -1
console.log(search2); // 0
let split1 = message1.split(hasLengthOf10),
 split2 = message2.split(hasLengthOf10);
console.log(split1); // ["Hello world"]
console.log(split2); // ["", ""]