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