prettier: support reading code from stdin (denoland#498)

prettier/README.md

@@ -6,22 +6,31 @@ Prettier APIs and tools for deno
 
 To formats the source files, run:
 
-```console
+```bash
 deno --allow-read --allow-write https://deno.land/std/prettier/main.ts
 ```
 
 You can format only specific files by passing the arguments.
 
-```console
+```bash
 deno --allow-read --allow-write https://deno.land/std/prettier/main.ts path/to/script.ts
 ```
 
 You can format files on specific directory by passing the directory's path.
 
-```console
+```bash
 deno --allow-read --allow-write https://deno.land/std/prettier/main.ts path/to/script.ts
 ```
 
+You can format the input plain text stream. default parse it as typescript code.
+
+```bash
+cat path/to/script.ts | deno https://deno.land/std/prettier/main.ts
+cat path/to/script.js | deno https://deno.land/std/prettier/main.ts --stdin-parser=babel
+cat path/to/config.json | deno https://deno.land/std/prettier/main.ts --stdin-parser=json
+cat path/to/README.md | deno https://deno.land/std/prettier/main.ts --stdin-parser=markdown
+```
+
 ## Use API
 
 You can use APIs of prettier as the following:

prettier/main.ts

@@ -23,7 +23,7 @@
 // Copyright 2018-2019 the Deno authors. All rights reserved. MIT license.
 // This script formats the given source files. If the files are omitted, it
 // formats the all files in the repository.
-const { args, exit, readFile, writeFile, stdout } = Deno;
+const { args, exit, readFile, writeFile, stdout, stdin, readAll } = Deno;
 import { glob, isGlob, GlobOptions } from "../fs/glob.ts";
 import { walk, WalkInfo } from "../fs/walk.ts";
 import { parse } from "../flags/mod.ts";
@@ -41,6 +41,15 @@ Options:
                                         it will output to stdout, Defaults to
                                         false.
   --ignore <path>                       Ignore the given path(s).
+  --stdin                               Specifies to read the code from stdin.
+                                        If run the command in a pipe, you do not
+                                        need to specify this flag.
+                                        Defaults to false.
+  --stdin-parser <typescript|babel|markdown|json>
+                                        If set --stdin flag, then need specify a
+                                        parser for stdin. available parser:
+                                        typescript/babel/markdown/json. Defaults
+                                        to typescript.
 
 JS/TS Styling Options:
   --print-width <int>                   The line length where Prettier will try
@@ -76,6 +85,14 @@ Example:
 
   deno run prettier/main.ts script1.ts
                                         Print the formatted code to stdout
+
+  cat script1.ts | deno run prettier/main.ts
+                                        Read the typescript code from stdin and
+                                        output formatted code to stdout.
+
+  cat config.json | deno run prettier/main.ts --stdin-parser=json
+                                        Read the JSON string from stdin and
+                                        output formatted code to stdout.
 `;
 
 // Available parsers
@@ -237,6 +254,39 @@ async function formatSourceFiles(
   exit(0);
 }
 
+/**
+ * Format source code
+ */
+function format(
+  text: string,
+  parser: ParserLabel,
+  prettierOpts: PrettierOptions
+): string {
+  const formatted: string = prettier.format(text, {
+    ...prettierOpts,
+    parser: parser,
+    plugins: prettierPlugins
+  });
+
+  return formatted;
+}
+
+/**
+ * Format code from stdin and output to stdout
+ */
+async function formatFromStdin(
+  parser: ParserLabel,
+  prettierOpts: PrettierOptions
+): Promise<void> {
+  const byte = await readAll(stdin);
+  const formattedCode = format(
+    new TextDecoder().decode(byte),
+    parser,
+    prettierOpts
+  );
+  await stdout.write(new TextEncoder().encode(formattedCode));
+}
+
 /**
  * Get the files to format.
  * @param selectors The glob patterns to select the files.
@@ -329,14 +379,21 @@ async function main(opts): Promise<void> {
     options
   );
 
+  const tty = Deno.isTTY();
+
+  const shouldReadFromStdin =
+    (!tty.stdin && (tty.stdout || tty.stderr)) || !!opts["stdin"];
+
   try {
-    if (check) {
+    if (shouldReadFromStdin) {
+      await formatFromStdin(opts["stdin-parser"], prettierOpts);
+    } else if (check) {
       await checkSourceFiles(files, prettierOpts);
     } else {
       await formatSourceFiles(files, prettierOpts);
     }
   } catch (e) {
-    console.log(e);
+    console.error(e);
     exit(1);
   }
 }
@@ -350,7 +407,8 @@ main(
       "trailing-comma",
       "arrow-parens",
       "prose-wrap",
-      "end-of-line"
+      "end-of-line",
+      "stdin-parser"
     ],
     boolean: [
       "check",
@@ -359,7 +417,8 @@ main(
       "use-tabs",
       "single-quote",
       "bracket-spacing",
-      "write"
+      "write",
+      "stdin"
     ],
     default: {
       ignore: [],
@@ -373,7 +432,9 @@ main(
       "arrow-parens": "avoid",
       "prose-wrap": "preserve",
       "end-of-line": "auto",
-      write: false
+      write: false,
+      stdin: false,
+      "stdin-parser": "typescript"
     },
     alias: {
       H: "help"

prettier/main_test.ts

@@ -2,7 +2,7 @@
 import { join } from "../fs/path.ts";
 import { EOL } from "../fs/path/constants.ts";
 import { assertEquals } from "../testing/asserts.ts";
-import { test } from "../testing/mod.ts";
+import { test, runIfMain } from "../testing/mod.ts";
 import { xrun } from "./util.ts";
 import { copy, emptyDir } from "../fs/mod.ts";
 const { readAll, execPath } = Deno;
@@ -233,3 +233,128 @@ test(async function testPrettierPrintToStdout(): Promise<void> {
 
   emptyDir(tempDir);
 });
+
+test(async function testPrettierReadFromStdin(): Promise<void> {
+  interface TestCase {
+    stdin: string;
+    stdout: string;
+    stderr: string;
+    code: number;
+    success: boolean;
+    parser?: string;
+  }
+
+  async function readFromStdinAssertion(
+    stdin: string,
+    expectedStdout: string,
+    expectedStderr: string,
+    expectedCode: number,
+    expectedSuccess: boolean,
+    parser?: string
+  ): Promise<void> {
+    const inputCode = stdin;
+    const p1 = Deno.run({
+      args: [execPath, "./prettier/testdata/echox.ts", `${inputCode}`],
+      stdout: "piped"
+    });
+
+    const p2 = Deno.run({
+      args: [
+        execPath,
+        "run",
+        "./prettier/main.ts",
+        "--stdin",
+        ...(parser ? ["--stdin-parser", parser] : [])
+      ],
+      stdin: "piped",
+      stdout: "piped",
+      stderr: "piped"
+    });
+
+    const n = await Deno.copy(p2.stdin!, p1.stdout!);
+    assertEquals(n, new TextEncoder().encode(stdin).length);
+
+    const status1 = await p1.status();
+    assertEquals(status1.code, 0);
+    assertEquals(status1.success, true);
+    p2.stdin!.close();
+    const status2 = await p2.status();
+    assertEquals(status2.code, expectedCode);
+    assertEquals(status2.success, expectedSuccess);
+    const decoder = new TextDecoder("utf-8");
+    assertEquals(
+      decoder.decode(await Deno.readAll(p2.stdout!)),
+      expectedStdout
+    );
+    assertEquals(
+      decoder.decode(await Deno.readAll(p2.stderr!)).split(EOL)[0],
+      expectedStderr
+    );
+    p2.close();
+    p1.close();
+  }
+
+  const testCases: TestCase[] = [
+    {
+      stdin: `console.log("abc"  )`,
+      stdout: `console.log("abc");\n`,
+      stderr: ``,
+      code: 0,
+      success: true
+    },
+    {
+      stdin: `console.log("abc"  )`,
+      stdout: `console.log("abc");\n`,
+      stderr: ``,
+      code: 0,
+      success: true,
+      parser: "babel"
+    },
+    {
+      stdin: `{\"a\":\"b\"}`,
+      stdout: `{ "a": "b" }\n`,
+      stderr: ``,
+      code: 0,
+      success: true,
+      parser: "json"
+    },
+    {
+      stdin: `##  test`,
+      stdout: `## test\n`,
+      stderr: ``,
+      code: 0,
+      success: true,
+      parser: "markdown"
+    },
+    {
+      stdin: `invalid typescript code##!!@@`,
+      stdout: ``,
+      stderr: `SyntaxError: ';' expected. (1:9)`,
+      code: 1,
+      success: false
+    },
+    {
+      stdin: `console.log("foo");`,
+      stdout: ``,
+      stderr:
+        'Error: Couldn\'t resolve parser "invalid_parser". ' +
+        "Parsers must be explicitly added to the standalone bundle.",
+      code: 1,
+      success: false,
+      parser: "invalid_parser"
+    }
+  ];
+
+  for (const t of testCases) {
+    await readFromStdinAssertion(
+      t.stdin,
+      t.stdout,
+      t.stderr,
+      t.code,
+      t.success,
+      t.parser
+    );
+  }
+});
+
+runIfMain(import.meta);

prettier/testdata/echox.ts

@@ -0,0 +1,8 @@
+async function echox(args: string[]) {
+  for (const arg of args) {
+    await Deno.stdout.write(new TextEncoder().encode(arg));
+  }
+  Deno.exit(0);
+}
+
+echox(Deno.args.slice(1));