loose-equal.js
1.58 KB
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import { hasOwnProperty, keys } from './object'
import { isArray, isDate, isObject } from './inspect'
// Assumes both a and b are arrays!
// Handles when arrays are "sparse" (array.every(...) doesn't handle sparse)
const compareArrays = (a, b) => {
if (a.length !== b.length) {
return false
}
let equal = true
for (let i = 0; equal && i < a.length; i++) {
equal = looseEqual(a[i], b[i])
}
return equal
}
/**
* Check if two values are loosely equal - that is,
* if they are plain objects, do they have the same shape?
* Returns boolean true or false
*/
export const looseEqual = (a, b) => {
if (a === b) {
return true
}
let aValidType = isDate(a)
let bValidType = isDate(b)
if (aValidType || bValidType) {
return aValidType && bValidType ? a.getTime() === b.getTime() : false
}
aValidType = isArray(a)
bValidType = isArray(b)
if (aValidType || bValidType) {
return aValidType && bValidType ? compareArrays(a, b) : false
}
aValidType = isObject(a)
bValidType = isObject(b)
if (aValidType || bValidType) {
/* istanbul ignore if: this if will probably never be called */
if (!aValidType || !bValidType) {
return false
}
const aKeysCount = keys(a).length
const bKeysCount = keys(b).length
if (aKeysCount !== bKeysCount) {
return false
}
for (const key in a) {
const aHasKey = hasOwnProperty(a, key)
const bHasKey = hasOwnProperty(b, key)
if ((aHasKey && !bHasKey) || (!aHasKey && bHasKey) || !looseEqual(a[key], b[key])) {
return false
}
}
}
return String(a) === String(b)
}