[Fix] fromBase64, setFromBase64: Safari 18.5 fails to throw on odd length strings

ljharb · ljharb · commit dd319af40d35 · 2025-07-07T13:47:26.000-07:00
diff --git a/README.md b/README.md
@@ -26,6 +26,11 @@ If `Uint8Array` is not present, the `shim` functions and `auto` entrypoints will
  - [`Uint8Array.prototype.setFromBase64`](https://tc39.es/proposal-arraybuffer-base64/spec/#sec-uint8array.prototype.setfrombase64)
  - [`Uint8Array.prototype.setFromHex`](https://tc39.es/proposal-arraybuffer-base64/spec/#sec-uint8array.prototype.setfromhex)
 
+## When you need this package
+
+ - When you are using an engine that does not support any of the above methods
+ - When using Safari 18.5 or earlier, which fails to throw on odd-length hex strings
+
 ## Getting started
 
 ```sh
diff --git a/Uint8Array.fromBase64/polyfill.js b/Uint8Array.fromBase64/polyfill.js
@@ -3,5 +3,12 @@
 var implementation = require('./implementation');
 
 module.exports = function getPolyfill() {
-	return typeof Uint8Array === 'function' && typeof Uint8Array.fromBase64 === 'function' ? Uint8Array.fromBase64 : implementation;
+	if (typeof Uint8Array === 'function' && typeof Uint8Array.fromBase64 === 'function') {
+		try {
+			Uint8Array.fromBase64('a');
+		} catch (e) {
+			return Uint8Array.fromBase64;
+		}
+	}
+	return implementation;
 };
diff --git a/Uint8Array.prototype.setFromBase64/polyfill.js b/Uint8Array.prototype.setFromBase64/polyfill.js
@@ -3,5 +3,12 @@
 var implementation = require('./implementation');
 
 module.exports = function getPolyfill() {
-	return typeof Uint8Array === 'function' && typeof Uint8Array.prototype.setFromBase64 === 'function' ? Uint8Array.prototype.setFromBase64 : implementation;
+	if (typeof Uint8Array === 'function' && typeof Uint8Array.setFromBase64 === 'function') {
+		try {
+			Uint8Array.setFromBase64('a');
+		} catch (e) {
+			return Uint8Array.setFromBase64;
+		}
+	}
+	return implementation;
 };
diff --git a/package.json b/package.json
@@ -124,5 +124,8 @@
 		"ignore": [
 			".github/workflows"
 		]
+	},
+	"testling": {
+		"files": "test/shimmed.js"
 	}
 }
diff --git a/test/Uint8Array.fromBase64.js b/test/Uint8Array.fromBase64.js
@@ -17,7 +17,7 @@ var shimName = 'Uint8Array.fromBase64';
 
 module.exports = {
 	tests: function (t, method) {
-		t.test('Uint8Arrays not supported', { skip: typeof Uint8Array === 'function' }, function (st) {
+		t.test('when Uint8Arrays not supported', { skip: typeof Uint8Array === 'function' }, function (st) {
 			st['throws'](
 				function () { return method(''); },
 				SyntaxError,
diff --git a/test/Uint8Array.fromHex.js b/test/Uint8Array.fromHex.js
@@ -16,7 +16,7 @@ var shimName = 'Uint8Array.fromHex';
 
 module.exports = {
 	tests: function (t, method) {
-		t.test('Uint8Arrays not supported', { skip: typeof Uint8Array === 'function' }, function (st) {
+		t.test('when Uint8Arrays not supported', { skip: typeof Uint8Array === 'function' }, function (st) {
 			st['throws'](
 				function () { return method(''); },
 				SyntaxError,
diff --git a/test/Uint8Array.prototype.setFromBase64.js b/test/Uint8Array.prototype.setFromBase64.js
@@ -21,7 +21,7 @@ var shimName = 'Uint8Array.prototype.setFromBase64';
 
 module.exports = {
 	tests: function (t, method) {
-		t.test('Uint8Arrays not supported', { skip: typeof Uint8Array === 'function' }, function (st) {
+		t.test('when Uint8Arrays not supported', { skip: typeof Uint8Array === 'function' }, function (st) {
 			st['throws'](
 				function () { return method(''); },
 				SyntaxError,
diff --git a/test/Uint8Array.prototype.setFromHex.js b/test/Uint8Array.prototype.setFromHex.js
@@ -21,7 +21,7 @@ var shimName = 'Uint8Array.prototype.setFromHex';
 
 module.exports = {
 	tests: function (t, method) {
-		t.test('Uint8Arrays not supported', { skip: typeof Uint8Array === 'function' }, function (st) {
+		t.test('when Uint8Arrays not supported', { skip: typeof Uint8Array === 'function' }, function (st) {
 			st['throws'](
 				function () { return method(''); },
 				SyntaxError,
diff --git a/test/Uint8Array.prototype.toBase64.js b/test/Uint8Array.prototype.toBase64.js
@@ -23,7 +23,7 @@ var shimName = 'Uint8Array.prototype.' + methodName;
 
 module.exports = {
 	tests: function (t, method) {
-		t.test('Uint8Arrays not supported', { skip: typeof Uint8Array === 'function' }, function (st) {
+		t.test('when Uint8Arrays not supported', { skip: typeof Uint8Array === 'function' }, function (st) {
 			st['throws'](
 				function () { return method(); },
 				SyntaxError,
diff --git a/test/Uint8Array.prototype.toHex.js b/test/Uint8Array.prototype.toHex.js
@@ -24,7 +24,7 @@ var shimName = 'Uint8Array.prototype.' + methodName;
 
 module.exports = {
 	tests: function (t, method) {
-		t.test('Uint8Arrays not supported', { skip: typeof Uint8Array === 'function' }, function (st) {
+		t.test('when Uint8Arrays not supported', { skip: typeof Uint8Array === 'function' }, function (st) {
 			st['throws'](
 				function () { return method(); },
 				SyntaxError,
diff --git a/test/shimmed.js b/test/shimmed.js
@@ -3,22 +3,29 @@
 require('../auto');
 
 var test = require('tape');
-var forEach = require('es-abstract/helpers/forEach');
 
 var shims = require('../');
 
-forEach(shims, function (shim) {
-	var shimTests;
-	try {
-		shimTests = require('./' + shim); // eslint-disable-line global-require
-	} catch (e) {
-		test(shim + ': shimmed', { todo: true });
-	}
-	if (shimTests) {
-		shimTests.shimmed();
-	}
+test('shim list', function (t) {
+	t.deepEqual(shims, [
+		'Uint8Array.fromBase64',
+		'Uint8Array.fromHex',
+		'Uint8Array.prototype.setFromBase64',
+		'Uint8Array.prototype.setFromHex',
+		'Uint8Array.prototype.toBase64',
+		'Uint8Array.prototype.toHex'
+	], 'shim list is as expected');
+
+	t.end();
 });
 
+require('./Uint8Array.fromBase64').shimmed();
+require('./Uint8Array.fromHex').shimmed();
+require('./Uint8Array.prototype.setFromBase64').shimmed();
+require('./Uint8Array.prototype.setFromHex').shimmed();
+require('./Uint8Array.prototype.toBase64').shimmed();
+require('./Uint8Array.prototype.toHex').shimmed();
+
 test('integration', { skip: typeof Uint8Array !== 'function' }, function (t) {
 	var array = new Uint8Array([72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100]);
 	var hex = '48656c6c6f20576f726c64';

Original file line number	Diff line number	Diff line change
`@@ -124,5 +124,8 @@`
`124`	`124`	`"ignore": [`
`125`	`125`	`".github/workflows"`
`126`	`126`	`]`
	`127`	`+ },`
	`128`	`+ "testling": {`
	`129`	`+ "files": "test/shimmed.js"`
`127`	`130`	`}`
`128`	`131`	`}`