Memoize TS API version checks

extensions/typescript/src/utils/api.ts

@@ -7,6 +7,9 @@ import * as semver from 'semver';
 import * as nls from 'vscode-nls';
 const localize = nls.loadMessageBundle();
 
+import { memoize } from './memoize';
+
+
 export default class API {
 	public static readonly defaultVersion = new API('1.0.0', '1.0.0');
 
@@ -29,50 +32,62 @@ export default class API {
 		private readonly version: string
 	) { }
 
+	@memoize
 	public has203Features(): boolean {
 		return semver.gte(this.version, '2.0.3');
 	}
 
+	@memoize
 	public has206Features(): boolean {
 		return semver.gte(this.version, '2.0.6');
 	}
 
+	@memoize
 	public has208Features(): boolean {
 		return semver.gte(this.version, '2.0.8');
 	}
 
+	@memoize
 	public has213Features(): boolean {
 		return semver.gte(this.version, '2.1.3');
 	}
 
+	@memoize
 	public has220Features(): boolean {
 		return semver.gte(this.version, '2.2.0');
 	}
 
+	@memoize
 	public has222Features(): boolean {
 		return semver.gte(this.version, '2.2.2');
 	}
 
+	@memoize
 	public has230Features(): boolean {
 		return semver.gte(this.version, '2.3.0');
 	}
 
+	@memoize
 	public has234Features(): boolean {
 		return semver.gte(this.version, '2.3.4');
 	}
 
+	@memoize
 	public has240Features(): boolean {
 		return semver.gte(this.version, '2.4.0');
 	}
 
+	@memoize
 	public has250Features(): boolean {
 		return semver.gte(this.version, '2.5.0');
 	}
 
+	@memoize
 	public has260Features(): boolean {
 		return semver.gte(this.version, '2.6.0');
 	}
 
+	@memoize
 	public has262Features(): boolean {
 		return semver.gte(this.version, '2.6.2');
 	}

extensions/typescript/src/utils/memoize.ts

@@ -0,0 +1,34 @@
+/*---------------------------------------------------------------------------------------------
+ *  Copyright (c) Microsoft Corporation. All rights reserved.
+ *  Licensed under the MIT License. See License.txt in the project root for license information.
+ *--------------------------------------------------------------------------------------------*/
+
+export function memoize(_target: any, key: string, descriptor: any) {
+	let fnKey: string | undefined = undefined;
+	let fn: Function | undefined = undefined;
+
+	if (typeof descriptor.value === 'function') {
+		fnKey = 'value';
+		fn = descriptor.value;
+	} else if (typeof descriptor.get === 'function') {
+		fnKey = 'get';
+		fn = descriptor.get;
+	} else {
+		throw new Error('not supported');
+	}
+
+	const memoizeKey = `$memoize$${key}`;
+
+	descriptor[fnKey] = function (...args: any[]) {
+		if (!this.hasOwnProperty(memoizeKey)) {
+			Object.defineProperty(this, memoizeKey, {
+				configurable: false,
+				enumerable: false,
+				writable: false,
+				value: fn!.apply(this, args)
+			});
+		}
+
+		return this[memoizeKey];
+	};
+}

extensions/typescript/tsconfig.json

@@ -12,7 +12,8 @@
 		"noUnusedLocals": true,
 		"noUnusedParameters": true,
 		"strict": true,
-		"alwaysStrict": true
+		"alwaysStrict": true,
+		"experimentalDecorators": true
 	},
 	"include": [
 		"src/**/*"