JavaScript - number truncation (getting total part)

In this short article, we would like to show how to truncate numbers in JavaScript.

As truncation, we understand the total part of number extracting, keeping number sign.

Quick solution:

// ONLINE-RUNNER:browser;

// ES5 and older
var number = 3.14;
console.log(number < 0 ? Math.ceil(number) : Math.floor(number));  // 3

// ES6+
console.log(Math.trunc(3.14));  // 3

Alternative approaches

It is possible to get the same effect with bit operators (Bitwise Shift, Bitwise OR, and Bitwise NOT).

Warning: the solution converts numbers to 32 bits.

// ONLINE-RUNNER:browser;

console.log(3.14 << 0);  // 3
console.log(3.14 >> 0);  // 3

console.log(3.14 | 0);   // 3

console.log(~~3.14);     // 3

See also

1. JavaScript - how to get decimal part of float number?