es-toolkit
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A state-of-the-art, high-performance JavaScript utility library with a small bundle size and strong type annotations.
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JavaScript
import { getSymbols } from "../compat/_internal/getSymbols.mjs";
import { getTag } from "../compat/_internal/getTag.mjs";
import { arrayBufferTag, arrayTag, bigInt64ArrayTag, bigUint64ArrayTag, booleanTag, dataViewTag, dateTag, errorTag, float32ArrayTag, float64ArrayTag, functionTag, int16ArrayTag, int32ArrayTag, int8ArrayTag, mapTag, numberTag, objectTag, regexpTag, setTag, stringTag, symbolTag, uint16ArrayTag, uint32ArrayTag, uint8ArrayTag, uint8ClampedArrayTag } from "../compat/_internal/tags.mjs";
import { isBuffer } from "./isBuffer.mjs";
import { isPlainObject } from "./isPlainObject.mjs";
import { eq } from "../compat/util/eq.mjs";
//#region src/predicate/isEqualWith.ts
/**
* Compares two values for equality using a custom comparison function.
*
* The custom function allows for fine-tuned control over the comparison process. If it returns a boolean, that result determines the equality. If it returns undefined, the function falls back to the default equality comparison.
*
* This function also uses the custom equality function to compare values inside objects,
* arrays, maps, sets, and other complex structures, ensuring a deep comparison.
*
* This approach provides flexibility in handling complex comparisons while maintaining efficient default behavior for simpler cases.
*
* The custom comparison function can take up to six parameters:
* - `x`: The value from the first object `a`.
* - `y`: The value from the second object `b`.
* - `property`: The property key used to get `x` and `y`.
* - `xParent`: The parent of the first value `x`.
* - `yParent`: The parent of the second value `y`.
* - `stack`: An internal stack (Map) to handle circular references.
*
* @param a - The first value to compare.
* @param b - The second value to compare.
* @param areValuesEqual - A function to customize the comparison.
* If it returns a boolean, that result will be used. If it returns undefined,
* the default equality comparison will be used.
* @returns `true` if the values are equal according to the customizer, otherwise `false`.
*
* @example
* const customizer = (a, b) => {
* if (typeof a === 'string' && typeof b === 'string') {
* return a.toLowerCase() === b.toLowerCase();
* }
* };
* isEqualWith('Hello', 'hello', customizer); // true
* isEqualWith({ a: 'Hello' }, { a: 'hello' }, customizer); // true
* isEqualWith([1, 2, 3], [1, 2, 3], customizer); // true
*/
function isEqualWith(a, b, areValuesEqual) {
return isEqualWithImpl(a, b, void 0, void 0, void 0, void 0, areValuesEqual);
}
function isEqualWithImpl(a, b, property, aParent, bParent, stack, areValuesEqual) {
const result = areValuesEqual(a, b, property, aParent, bParent, stack);
if (result !== void 0) return result;
if (typeof a === typeof b) switch (typeof a) {
case "bigint":
case "string":
case "boolean":
case "symbol":
case "undefined": return a === b;
case "number": return a === b || Object.is(a, b);
case "function": return a === b;
case "object": return areObjectsEqual(a, b, stack, areValuesEqual);
}
return areObjectsEqual(a, b, stack, areValuesEqual);
}
function areObjectsEqual(a, b, stack, areValuesEqual) {
if (Object.is(a, b)) return true;
let aTag = getTag(a);
let bTag = getTag(b);
if (aTag === "[object Arguments]") aTag = objectTag;
if (bTag === "[object Arguments]") bTag = objectTag;
if (aTag !== bTag) return false;
switch (aTag) {
case stringTag: return a.toString() === b.toString();
case numberTag: return eq(a.valueOf(), b.valueOf());
case booleanTag:
case dateTag:
case symbolTag: return Object.is(a.valueOf(), b.valueOf());
case regexpTag: return a.source === b.source && a.flags === b.flags;
case functionTag: return a === b;
}
stack = stack ?? /* @__PURE__ */ new Map();
const aStack = stack.get(a);
const bStack = stack.get(b);
if (aStack != null && bStack != null) return aStack === b;
stack.set(a, b);
stack.set(b, a);
try {
switch (aTag) {
case mapTag:
if (a.size !== b.size) return false;
for (const [key, value] of a.entries()) if (!b.has(key) || !isEqualWithImpl(value, b.get(key), key, a, b, stack, areValuesEqual)) return false;
return true;
case setTag: {
if (a.size !== b.size) return false;
const aValues = Array.from(a.values());
const bValues = Array.from(b.values());
for (let i = 0; i < aValues.length; i++) {
const aValue = aValues[i];
const index = bValues.findIndex((bValue) => {
return isEqualWithImpl(aValue, bValue, void 0, a, b, stack, areValuesEqual);
});
if (index === -1) return false;
bValues.splice(index, 1);
}
return true;
}
case arrayTag:
case uint8ArrayTag:
case uint8ClampedArrayTag:
case uint16ArrayTag:
case uint32ArrayTag:
case bigUint64ArrayTag:
case int8ArrayTag:
case int16ArrayTag:
case int32ArrayTag:
case bigInt64ArrayTag:
case float32ArrayTag:
case float64ArrayTag:
if (isBuffer(a) !== isBuffer(b)) return false;
if (a.length !== b.length) return false;
for (let i = 0; i < a.length; i++) if (!isEqualWithImpl(a[i], b[i], i, a, b, stack, areValuesEqual)) return false;
return true;
case arrayBufferTag:
if (a.byteLength !== b.byteLength) return false;
return areObjectsEqual(new Uint8Array(a), new Uint8Array(b), stack, areValuesEqual);
case dataViewTag:
if (a.byteLength !== b.byteLength || a.byteOffset !== b.byteOffset) return false;
return areObjectsEqual(new Uint8Array(a), new Uint8Array(b), stack, areValuesEqual);
case errorTag: return a.name === b.name && a.message === b.message;
case objectTag: {
if (!(areObjectsEqual(a.constructor, b.constructor, stack, areValuesEqual) || isPlainObject(a) && isPlainObject(b))) return false;
const aKeys = [...Object.keys(a), ...getSymbols(a)];
const bKeys = [...Object.keys(b), ...getSymbols(b)];
if (aKeys.length !== bKeys.length) return false;
for (let i = 0; i < aKeys.length; i++) {
const propKey = aKeys[i];
const aProp = a[propKey];
if (!Object.hasOwn(b, propKey)) return false;
const bProp = b[propKey];
if (!isEqualWithImpl(aProp, bProp, propKey, a, b, stack, areValuesEqual)) return false;
}
return true;
}
default: return false;
}
} finally {
stack.delete(a);
stack.delete(b);
}
}
//#endregion
export { isEqualWith };