[Fix] node < v0.6 lacks proper Object toString behavior

This also removes the `is-typed-array` dependency, which will be refactored to use this package instead

index.js

@@ -13,44 +13,77 @@ var g = typeof globalThis === 'undefined' ? global : globalThis;
 var typedArrays = availableTypedArrays();
 
 var $slice = callBound('String.prototype.slice');
-var toStrTags = { __proto__: null };
 var getPrototypeOf = Object.getPrototypeOf; // require('getprototypeof');
+
+var $indexOf = callBound('Array.prototype.indexOf', true) || function indexOf(array, value) {
+	for (var i = 0; i < array.length; i += 1) {
+		if (array[i] === value) {
+			return i;
+		}
+	}
+	return -1;
+};
+var cache = { __proto__: null };
 if (hasToStringTag && gOPD && getPrototypeOf) {
 	forEach(typedArrays, function (typedArray) {
-		if (typeof g[typedArray] === 'function') {
-			var arr = new g[typedArray]();
-			if (Symbol.toStringTag in arr) {
-				var proto = getPrototypeOf(arr);
-				var descriptor = gOPD(proto, Symbol.toStringTag);
-				if (!descriptor) {
-					var superProto = getPrototypeOf(proto);
-					descriptor = gOPD(superProto, Symbol.toStringTag);
-				}
-				toStrTags[typedArray] = callBind(descriptor.get);
+		var arr = new g[typedArray]();
+		if (Symbol.toStringTag in arr) {
+			var proto = getPrototypeOf(arr);
+			var descriptor = gOPD(proto, Symbol.toStringTag);
+			if (!descriptor) {
+				var superProto = getPrototypeOf(proto);
+				descriptor = gOPD(superProto, Symbol.toStringTag);
 			}
+			cache['$' + typedArray] = callBind(descriptor.get);
 		}
 	});
+} else {
+	forEach(typedArrays, function (typedArray) {
+		var arr = new g[typedArray]();
+		cache['$' + typedArray] = callBind(arr.slice);
+	});
 }
 
 var tryTypedArrays = function tryAllTypedArrays(value) {
-	var foundName = false;
-	forEach(toStrTags, function (getter, typedArray) {
-		if (!foundName) {
+	var found = false;
+	forEach(cache, function (getter, typedArray) {
+		if (!found) {
 			try {
-				var name = getter(value);
-				if (name === typedArray) {
-					foundName = name;
+				if ('$' + getter(value) === typedArray) {
+					found = $slice(typedArray, 1);
 				}
-			} catch (e) {}
+			} catch (e) { /**/ }
 		}
 	});
-	return foundName;
+	return found;
 };
 
-var isTypedArray = require('is-typed-array');
+var trySlices = function tryAllSlices(value) {
+	var found = false;
+	forEach(cache, function (getter, name) {
+		if (!found) {
+			try {
+				getter(value);
+				found = $slice(name, 1);
+			} catch (e) { /**/ }
+		}
+	});
+	return found;
+};
 
 module.exports = function whichTypedArray(value) {
-	if (!isTypedArray(value)) { return false; }
-	if (!hasToStringTag || !(Symbol.toStringTag in value)) { return $slice($toString(value), 8, -1); }
+	if (!value || typeof value !== 'object') { return false; }
+	if (!hasToStringTag) {
+		var tag = $slice($toString(value), 8, -1);
+		if ($indexOf(typedArrays, tag) > -1) {
+			return tag;
+		}
+		if (tag !== 'Object') {
+			return false;
+		}
+		// node < 0.6 hits here on real Typed Arrays
+		return trySlices(value);
+	}
+	if (!gOPD) { return null; } // unknown engine
 	return tryTypedArrays(value);
 };

package.json

@@ -62,8 +62,7 @@
 		"call-bind": "^1.0.2",
 		"for-each": "^0.3.3",
 		"gopd": "^1.0.1",
-		"has-tostringtag": "^1.0.0",
-		"is-typed-array": "^1.1.10"
+		"has-tostringtag": "^1.0.0"
 	},
 	"devDependencies": {
 		"@ljharb/eslint-config": "^21.1.0",

test/index.js

@@ -90,7 +90,7 @@ test('Typed Arrays', function (t) {
 		var TypedArray = global[typedArray];
 		if (isCallable(TypedArray)) {
 			var arr = new TypedArray(10);
-			t.equal(typedArray, whichTypedArray(arr), 'new ' + typedArray + '(10) is typed array of type ' + typedArray);
+			t.equal(whichTypedArray(arr), typedArray, 'new ' + typedArray + '(10) is typed array of type ' + typedArray);
 		} else {
 			t.comment('# SKIP ' + typedArray + ' is not supported');
 		}