work.suroh.tk/node_modules/is-number-like/lib/index.js

55 lines
1.2 KiB
JavaScript

'use strict'
var isNumber = require('lodash.isfinite')
/**
* @id isNumberLike
* @function isNumberLike
* Checks whether provided parameter looks like a number
* @param {any} val - the value to check
* @returns {boolean} looksLikeNumber - `true` if `val` looks like a number, `false` otherwise
*/
module.exports = function isNumberLike (val) {
// fail
if (val === null || val === void 0 || val === false) {
return false
}
if (typeof val === 'function' || val instanceof Array) {
return false
}
var length = val.length
if (!length) {
return isNumber(val)
}
var i = 0
// charAt is faster in v8
if (val.charAt(0) === '-') {
if (length === 1) {
// fail do it
return false
}
i = 1
}
var foundE = false
var foundPeriod = false
for (; i < length; i++) {
var c = val.charAt(i)
// bit range is outside number range
if ((c <= '/' || c >= ':')) {
if (c === 'e') {
if (foundE) {
return false
}
foundE = true
} else if (c === '.') {
if (foundPeriod) {
return false
}
foundPeriod = true
} else {
return false
}
}
}
return true
}