Month: December 2017

JavaScript’s typeof operator should be ignored. It’s broken.

JavaScript’s typeof operator should be ignored. It’s broken.

A more reliable test for data types:

Object.prototype.toString.call(data);

For example:

Object.prototype.toString.call([]); // [object Array]

Object.prototype.toString.call({}); // [object Object]

Object.prototype.toString.call(”); // [object String]

Object.prototype.toString.call(new Date()); // [object Date]

Object.prototype.toString.call(1); // [object Number]

Object.prototype.toString.call(function () {}); // [object Function]

Object.prototype.toString.call(/test/i); // [object RegExp]

Object.prototype.toString.call(true); // [object Boolean]

Object.prototype.toString.call(null); // [object Null]

Object.prototype.toString.call(); // [object Undefined]

https://toddmotto.com/understanding-javascript-types-and-reliable-type-checking/