Validate the input argument type

sindresorhus · Nov 2, 2018 · ba2fdde · ba2fdde
1 parent 7ab526a
commit ba2fdde
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Showing 2 changed files with 18 additions and 0 deletions.
diff --git a/index.js b/index.js
@@ -16,6 +16,10 @@ function readUInt64LE(buf, offset = 0) {
 }
 
 module.exports = input => {
+	if (!(input instanceof Uint8Array || Buffer.isBuffer(input))) {
+		throw new TypeError(`Expected the \`input\` argument to be of type \`Uint8Array\` or \`Buffer\`, got \`${typeof input}\``);
+	}
+
 	const buf = input instanceof Uint8Array ? input : new Uint8Array(input);
 
 	if (!(buf && buf.length > 1)) {

diff --git a/test.js b/test.js
@@ -197,3 +197,17 @@ for (const type of types) {
 test('fileType.minimumBytes', t => {
 	t.true(fileType.minimumBytes > 4000);
 });
+
+test('validate the input argument type', t => {
+	t.throws(() => {
+		fileType('x');
+	}, /Expected the `input` argument to be of type `Uint8Array`/);
+
+	t.notThrows(() => {
+		fileType(Buffer.from('x'));
+	});
+
+	t.notThrows(() => {
+		fileType(new Uint8Array());
+	});
+});