[Refactor] use set-function-length

Author: ljharb

index.js

@@ -2,12 +2,12 @@
 
 var bind = require('function-bind');
 var GetIntrinsic = require('get-intrinsic');
+var setFunctionLength = require('set-function-length');
 
 var $apply = GetIntrinsic('%Function.prototype.apply%');
 var $call = GetIntrinsic('%Function.prototype.call%');
 var $reflectApply = GetIntrinsic('%Reflect.apply%', true) || bind.call($call, $apply);
 
-var $gOPD = GetIntrinsic('%Object.getOwnPropertyDescriptor%', true);
 var $defineProperty = GetIntrinsic('%Object.defineProperty%', true);
 var $max = GetIntrinsic('%Math.max%');
 
@@ -22,18 +22,11 @@ if ($defineProperty) {
 
 module.exports = function callBind(originalFunction) {
 	var func = $reflectApply(bind, $call, arguments);
-	if ($gOPD && $defineProperty) {
-		var desc = $gOPD(func, 'length');
-		if (desc.configurable) {
-			// original length, plus the receiver, minus any additional arguments (after the receiver)
-			$defineProperty(
-				func,
-				'length',
-				{ value: 1 + $max(0, originalFunction.length - (arguments.length - 1)) }
-			);
-		}
-	}
-	return func;
+	return setFunctionLength(
+		func,
+		1 + $max(0, originalFunction.length - (arguments.length - 1)),
+		true
+	);
 };
 
 var applyBind = function applyBind() {

package.json

@@ -55,6 +55,8 @@
 		"auto-changelog": "^2.4.0",
 		"eslint": "=8.8.0",
 		"evalmd": "^0.0.19",
+		"gopd": "^1.0.1",
+		"has-strict-mode": "^1.0.1",
 		"in-publish": "^2.0.1",
 		"npmignore": "^0.3.0",
 		"nyc": "^10.3.2",
@@ -63,7 +65,11 @@
 	},
 	"dependencies": {
 		"function-bind": "^1.1.2",
-		"get-intrinsic": "^1.2.1"
+		"get-intrinsic": "^1.2.1",
+		"set-function-length": "^1.1.0"
+	},
+	"testling": {
+		"files": "test/index.js"
 	},
 	"auto-changelog": {
 		"output": "CHANGELOG.md",

test/index.js

@@ -2,6 +2,8 @@
 
 var callBind = require('../');
 var bind = require('function-bind');
+var gOPD = require('gopd');
+var hasStrictMode = require('has-strict-mode')();
 
 var test = require('tape');
 
@@ -10,15 +12,16 @@ var test = require('tape');
  * in io.js v3, it is configurable except on bound functions, hence the .bind()
  */
 var functionsHaveConfigurableLengths = !!(
-	Object.getOwnPropertyDescriptor
+	gOPD
+	&& Object.getOwnPropertyDescriptor
 	&& Object.getOwnPropertyDescriptor(bind.call(function () {}), 'length').configurable
 );
 
 test('callBind', function (t) {
 	var sentinel = { sentinel: true };
 	var func = function (a, b) {
 		// eslint-disable-next-line no-invalid-this
-		return [this, a, b];
+		return [!hasStrictMode && this === global ? undefined : this, a, b];
 	};
 	t.equal(func.length, 2, 'original function length is 2');
 	t.deepEqual(func(), [undefined, undefined, undefined], 'unbound func with too few args');
@@ -28,8 +31,8 @@ test('callBind', function (t) {
 	var bound = callBind(func);
 	t.equal(bound.length, func.length + 1, 'function length is preserved', { skip: !functionsHaveConfigurableLengths });
 	t.deepEqual(bound(), [undefined, undefined, undefined], 'bound func with too few args');
-	t.deepEqual(bound(1, 2), [1, 2, undefined], 'bound func with right args');
-	t.deepEqual(bound(1, 2, 3), [1, 2, 3], 'bound func with too many args');
+	t.deepEqual(bound(1, 2), [hasStrictMode ? 1 : Object(1), 2, undefined], 'bound func with right args');
+	t.deepEqual(bound(1, 2, 3), [hasStrictMode ? 1 : Object(1), 2, 3], 'bound func with too many args');
 
 	var boundR = callBind(func, sentinel);
 	t.equal(boundR.length, func.length, 'function length is preserved', { skip: !functionsHaveConfigurableLengths });