Added read file str (denoland/deno_std#276)

Original: b462ad2530

fs/read_file_str.ts

@@ -0,0 +1,33 @@
+// Copyright 2018-2019 the Deno authors. All rights reserved. MIT license.
+
+export interface ReadOptions {
+  encoding?: string;
+}
+
+/**
+ * Read file synchronously and output it as a string.
+ *
+ * @param filename File to read
+ * @param opts Read options
+ */
+export function readFileStrSync(
+  filename: string,
+  opts: ReadOptions = {}
+): string {
+  const decoder = new TextDecoder(opts.encoding);
+  return decoder.decode(Deno.readFileSync(filename));
+}
+
+/**
+ * Read file and output it as a string.
+ *
+ * @param filename File to read
+ * @param opts Read options
+ */
+export async function readFileStr(
+  filename: string,
+  opts: ReadOptions = {}
+): Promise<string> {
+  const decoder = new TextDecoder(opts.encoding);
+  return decoder.decode(await Deno.readFile(filename));
+}

fs/read_file_str_test.ts

@@ -0,0 +1,20 @@
+import { test } from "../testing/mod.ts";
+import { assert } from "../testing/asserts.ts";
+import { readFileStrSync, readFileStr } from "./read_file_str.ts";
+import * as path from "./path/mod.ts";
+
+const testdataDir = path.resolve("fs", "testdata");
+
+test(function testReadFileSync() {
+  const jsonFile = path.join(testdataDir, "json_valid_obj.json");
+  const strFile = readFileStrSync(jsonFile);
+  assert(typeof strFile === "string");
+  assert(strFile.length > 0);
+});
+
+test(async function testReadFile() {
+  const jsonFile = path.join(testdataDir, "json_valid_obj.json");
+  const strFile = await readFileStr(jsonFile);
+  assert(typeof strFile === "string");
+  assert(strFile.length > 0);
+});

fs/test.ts

@@ -10,5 +10,6 @@ import "./ensure_dir_test.ts";
 import "./ensure_file_test.ts";
 import "./move_test.ts";
 import "./read_json_test.ts";
+import "./read_file_str_test.ts";
 import "./write_json_test.ts";
 import "./utils_test.ts";