feat: add resetCache (#554)

README.md

@@ -4,7 +4,6 @@ Express Handlebars
 A [Handlebars][] view engine for [Express][] which doesn't suck.
 
 [![npm version][npm-badge]][npm]
-[![dependency status][dep-badge]][dep-status]
 
 **This package used to be named `express3-handlebars`. The previous `express-handlebars` package by @jneen can be found [here][jneen-exphbs].**
 
@@ -13,8 +12,6 @@ A [Handlebars][] view engine for [Express][] which doesn't suck.
 [Handlebars]: https://github.com/handlebars-lang/handlebars.js
 [npm]: https://www.npmjs.org/package/express-handlebars
 [npm-badge]: https://img.shields.io/npm/v/express-handlebars.svg?style=flat-square
-[dep-status]: https://david-dm.org/express-handlebars/express-handlebars
-[dep-badge]: https://img.shields.io/david/express-handlebars/express-handlebars.svg?style=flat-square
 [jneen-exphbs]: https://github.com/jneen/express-handlebars
 
 
@@ -477,6 +474,13 @@ Use `options.precompiled` to receive precompiled Handlebars templates — this i
 
   * `[precompiled=false]`: Whether precompiled templates should be provided, instead of a compiled Handlebars template function.
 
+#### `resetCache([filePathsOrFilter])`
+Reset template cache. The cache can be partially reset by providing a filter argument. If no argument is given the whole cache will be reset.
+
+**Parameters:**
+
+* `[filePathsOrFilter]`: Optional filter to reset part of the cache. This can be a file path, an array of file paths, or a filter function based on file path.
+
 #### `render(filePath, context, [options])`
 Renders the template at the specified `filePath` with the `context`, using this instance's `helpers` and partials by default, and returns a Promise for the resulting string.
 

lib/express-handlebars.ts

@@ -288,6 +288,24 @@ export default class ExpressHandlebars {
 		return promise;
 	}
 
+	resetCache (filePathsOrFilter?: string | string[] | ((template: string) => boolean)) {
+		let filePaths: string[] = [];
+
+		if (typeof filePathsOrFilter === "undefined") {
+			filePaths = Object.keys(this._fsCache);
+		} else if (typeof filePathsOrFilter === "string") {
+			filePaths = [filePathsOrFilter];
+		} else if (typeof filePathsOrFilter === "function") {
+			filePaths = Object.keys(this._fsCache).filter(filePathsOrFilter);
+		} else if (Array.isArray(filePathsOrFilter)) {
+			filePaths = filePathsOrFilter;
+		}
+
+		for (const filePath of filePaths) {
+			delete this._fsCache[filePath];
+		}
+	}
+
 	// -- Protected Hooks ----------------------------------------------------------
 
 	protected _compileTemplate (template: string, options: RuntimeOptions = {}): HandlebarsTemplateDelegate {

spec/express-handlebars.test.ts

@@ -566,6 +566,80 @@ describe("express-handlebars", () => {
 		});
 	});
 
+	describe("resetCache", () => {
+		test("should reset all cache", async () => {
+			const exphbs = expressHandlebars.create();
+			const dirPath = fixturePath("templates");
+			const template = fixturePath("templates/template.handlebars");
+			await exphbs.getTemplates(dirPath);
+			expect(exphbs._fsCache[template]).toBeDefined();
+			exphbs.resetCache();
+			expect(exphbs._fsCache).toEqual({});
+		});
+
+		test("should reset all cache with undefined", async () => {
+			const exphbs = expressHandlebars.create();
+			const dirPath = fixturePath("templates");
+			const template = fixturePath("templates/template.handlebars");
+			await exphbs.getTemplates(dirPath);
+			expect(exphbs._fsCache[template]).toBeDefined();
+			let undef: undefined;
+			exphbs.resetCache(undef);
+			expect(exphbs._fsCache).toEqual({});
+		});
+
+		test("should reset cached file path", async () => {
+			const exphbs = expressHandlebars.create();
+			const dirPath = fixturePath("templates");
+			const template = fixturePath("templates/template.handlebars");
+			await exphbs.getTemplates(dirPath);
+			expect(Object.keys(exphbs._fsCache).length).toEqual(4);
+			expect(exphbs._fsCache[template]).toBeDefined();
+			exphbs.resetCache(template);
+			expect(Object.keys(exphbs._fsCache).length).toEqual(3);
+			expect(exphbs._fsCache[template]).toBeUndefined();
+		});
+
+		test("should reset cached file paths", async () => {
+			const exphbs = expressHandlebars.create();
+			const dirPath = fixturePath("templates");
+			const template = fixturePath("templates/template.handlebars");
+			const templateLatin1 = fixturePath("templates/template-latin1.handlebars");
+			await exphbs.getTemplates(dirPath);
+			expect(Object.keys(exphbs._fsCache).length).toEqual(4);
+			expect(exphbs._fsCache[template]).toBeDefined();
+			expect(exphbs._fsCache[templateLatin1]).toBeDefined();
+			exphbs.resetCache([template, templateLatin1]);
+			expect(Object.keys(exphbs._fsCache).length).toEqual(2);
+			expect(exphbs._fsCache[template]).toBeUndefined();
+			expect(exphbs._fsCache[templateLatin1]).toBeUndefined();
+		});
+
+		test("should reset cached file based on filter", async () => {
+			const exphbs = expressHandlebars.create();
+			const dirPath = fixturePath("templates");
+			const templateLatin1 = fixturePath("templates/template-latin1.handlebars");
+			await exphbs.getTemplates(dirPath);
+			expect(Object.keys(exphbs._fsCache).length).toEqual(4);
+			expect(exphbs._fsCache[templateLatin1]).toBeDefined();
+			exphbs.resetCache((f) => f.includes("latin1"));
+			expect(Object.keys(exphbs._fsCache).length).toEqual(3);
+			expect(exphbs._fsCache[templateLatin1]).toBeUndefined();
+		});
+
+		test("should not error on invalid file path", async () => {
+			const exphbs = expressHandlebars.create();
+			const dirPath = fixturePath("templates");
+			const template = fixturePath("templates/invalid.handlebars");
+			await exphbs.getTemplates(dirPath);
+			expect(Object.keys(exphbs._fsCache).length).toEqual(4);
+			expect(exphbs._fsCache[template]).toBeUndefined();
+			exphbs.resetCache(template);
+			expect(Object.keys(exphbs._fsCache).length).toEqual(4);
+			expect(exphbs._fsCache[template]).toBeUndefined();
+		});
+	});
+
 	describe("hooks", () => {
 		describe("_compileTemplate", () => {
 			test("should call template with context and options", () => {