Fix no-new-buffer crash on TypeScript-ESLint (#560)

rules/no-new-buffer.js

@@ -1,15 +1,27 @@
 'use strict';
 const getDocumentationUrl = require('./utils/get-documentation-url');
 
-const inferMethod = arguments_ => (arguments_.length > 0 && typeof arguments_[0].value === 'number') ? 'alloc' : 'from';
+const inferMethod = arguments_ => {
+	if (arguments_.length > 0) {
+		const [firstArgument] = arguments_;
+		if (
+			firstArgument.type === 'Literal' &&
+			typeof firstArgument.value === 'number'
+		) {
+			return 'alloc';
+		}
+	}
+
+	return 'from';
+};
 
 const create = context => {
 	return {
 		'NewExpression[callee.name="Buffer"]': node => {
 			const method = inferMethod(node.arguments);
 			const range = [
 				node.range[0],
-				node.callee.end
+				node.callee.range[1]
 			];
 
 			context.report({

test/no-new-buffer.js

@@ -12,6 +12,10 @@ const ruleTester = avaRuleTester(test, {
 	}
 });
 
+const typescriptRuleTester = avaRuleTester(test, {
+	parser: require.resolve('@typescript-eslint/parser')
+});
+
 const allocError = {
 	ruleId: 'no-new-buffer',
 	message: '`new Buffer()` is deprecated, use `Buffer.alloc()` instead.'
@@ -79,3 +83,14 @@ ruleTester.run('no-new-buffer', rule, {
 		}
 	]
 });
+
+typescriptRuleTester.run('no-new-buffer', rule, {
+	valid: [],
+	invalid: [
+		{
+			code: 'new Buffer(input, encoding);',
+			errors: [fromError],
+			output: 'Buffer.from(input, encoding);'
+		}
+	]
+});