JAVASCRIPT

javascript regex Zero or one occurrence

// javascript regex Zero or one occurrence
let neighbor = /neighbou?r/;
console.log(neighbor.test("neighbour")); // true
console.log(neighbor.test("neighbor")); // true

javascript regex zero or more occurrence

// /x*/ - Regular Expression zero or more occurrence
console.log(/'d*'/.test("'123'"));// true
console.log(/'d*'/.test("''"));// true