locutus/esm/lua/math/type.js

Locutus other languages' standard libraries to JavaScript for fun and educational purposes

const LUA_MIN_INTEGER = -(2 ** 63);
const LUA_MAX_INTEGER = 2 ** 63 - 1;
export function type(value) {
    //      discuss at: https://locutus.io/lua/type/
    // parity verified: Lua 5.4
    //     original by: Kevin van Zonneveld (https://kvz.io)
    //          note 1: Mirrors math.type by classifying JavaScript numbers as integer, float, or nil-like null.
    //       example 1: type(1)
    //       returns 1: 'integer'
    //       example 2: type(1.5)
    //       returns 2: 'float'
    //       example 3: type('1')
    //       returns 3: null
    if (typeof value !== 'number') {
        return null;
    }
    return Number.isInteger(value) && value >= LUA_MIN_INTEGER && value <= LUA_MAX_INTEGER ? 'integer' : 'float';
}