SQL Operations Studio Public Preview 1 (0.23) release source code

dataprotocol-node/client/src/utils/is.ts

@@ -0,0 +1,55 @@
+/* --------------------------------------------------------------------------------------------
+ * Copyright (c) Microsoft Corporation. All rights reserved.
+ * Licensed under the Source EULA. See License.txt in the project root for license information.
+ * ------------------------------------------------------------------------------------------ */
+'use strict';
+
+const toString = Object.prototype.toString;
+
+export function defined(value: any): boolean {
+	return typeof value !== 'undefined';
+}
+
+export function undefined(value: any): boolean {
+	return typeof value === 'undefined';
+}
+
+export function nil(value: any): boolean {
+	return value === null;
+}
+
+export function boolean(value: any): value is boolean {
+	return value === true || value === false;
+}
+
+export function string(value: any): value is string {
+	return toString.call(value) === '[object String]';
+}
+
+export function number(value: any): value is number {
+	return toString.call(value) === '[object Number]';
+}
+
+export function error(value: any): value is Error {
+	return toString.call(value) === '[object Error]';
+}
+
+export function func(value: any): value is Function {
+	return toString.call(value) === '[object Function]';
+}
+
+export function array<T>(value: any): value is T[] {
+	return Array.isArray(value);
+}
+
+export function stringArray(value: any): value is string[] {
+	return array(value) && (<any[]>value).every(elem => string(elem));
+}
+
+export function typedArray<T>(value: any, check: (value: any) => boolean): value is T[] {
+	return Array.isArray(value) && (<any[]>value).every(check);
+}
+
+export function thenable<T>(value: any): value is Thenable<T> {
+	return value && func(value.then);
+}