New: --print-label option (fixes #23)

Author: mysticatea

README.md

@@ -43,6 +43,9 @@ Usage: npm-run-all [...tasks] [OPTIONS]
 
     -c, --continue-on-error     Set the flag to ignore errors to the current
                                 group of tasks.
+    -l, --print-label           Set the flag to print the task name as a prefix
+                                on each line of output, to the current group of
+                                tasks.
     --silent                    Set "silent" to the log level of npm.
 
     -p, --parallel [...tasks]   Run a group of tasks in parallel.

package.json

@@ -22,10 +22,12 @@
   },
   "dependencies": {
     "babel-runtime": "^6.3.13",
+    "chalk": "^1.1.3",
     "cross-spawn-async": "^2.1.9",
     "minimatch": "^3.0.0",
     "ps-tree": "^1.0.1",
-    "shell-quote": "^1.4.3"
+    "shell-quote": "^1.4.3",
+    "string.prototype.padend": "^3.0.0"
   },
   "devDependencies": {
     "babel-cli": "^6.4.0",

src/bin/help.js

@@ -23,6 +23,9 @@ Usage: npm-run-all [...tasks] [OPTIONS]
 
     -c, --continue-on-error     Set the flag to ignore errors to the current
                                 group of tasks.
+    -l, --print-label           Set the flag to print the task name as a prefix
+                                on each line of output, to the current group of
+                                tasks.
     --silent                    Set "silent" to the log level of npm.
 
     -p, --parallel [...tasks]   Run a group of tasks in parallel.

src/bin/main.js

@@ -65,6 +65,7 @@ function parse(args) {
     const groups = [{
         parallel: false,
         continueOnError: false,
+        printLabel: false,
         patterns: []
     }];
 
@@ -79,6 +80,7 @@ function parse(args) {
                 groups.push({
                     parallel: false,
                     continueOnError: arg === "-S",
+                    printLabel: false,
                     patterns: []
                 });
                 break;
@@ -89,6 +91,7 @@ function parse(args) {
                 groups.push({
                     parallel: true,
                     continueOnError: arg === "-P",
+                    printLabel: false,
                     patterns: []
                 });
                 break;
@@ -98,6 +101,11 @@ function parse(args) {
                 groups[groups.length - 1].continueOnError = true;
                 break;
 
+            case "-l":
+            case "--print-label":
+                groups[groups.length - 1].printLabel = true;
+                break;
+
             case "--silent":
                 // do nothing.
                 break;
@@ -145,7 +153,7 @@ export default function npmRunAll(args, stdout, stderr) {
         const {groups, packageConfig} = parse(args);
 
         return groups.reduce(
-            (prev, {patterns, parallel, continueOnError}) => {
+            (prev, {patterns, parallel, continueOnError, printLabel}) => {
                 if (patterns.length === 0) {
                     return prev;
                 }
@@ -157,6 +165,7 @@ export default function npmRunAll(args, stdout, stderr) {
                         stdin,
                         parallel,
                         continueOnError,
+                        printLabel,
                         packageConfig,
                         silent
                     }

src/lib/create-prefix-transform-stream.js

@@ -0,0 +1,87 @@
+/**
+ * @author Toru Nagashima
+ * @copyright 2016 Toru Nagashima. All rights reserved.
+ * See LICENSE file in root directory for full license.
+ */
+
+//------------------------------------------------------------------------------
+// Requirements
+//------------------------------------------------------------------------------
+
+import {Transform} from "stream";
+
+//------------------------------------------------------------------------------
+// Helpers
+//------------------------------------------------------------------------------
+
+const ALL_BR = /\n/g;
+
+/**
+ * The transform stream to insert a specific prefix.
+ *
+ * Several streams can exist for the same output stream.
+ * This stream will insert the prefix if the last output came from other instance.
+ * To do that, this stream is using a shared state object.
+ *
+ * @private
+ */
+class PrefixTransform extends Transform {
+    /**
+     * @param {string} prefix - A prefix text to be inserted.
+     * @param {object} state - A state object.
+     * @param {string} state.lastPrefix - The last prefix which is printed.
+     * @param {boolean} state.lastIsLinebreak -The flag to check whether the last output is a line break or not.
+     */
+    constructor(prefix, state) {
+        super();
+
+        this.prefix = prefix;
+        this.state = state;
+    }
+
+    /**
+     * Transforms the output chunk.
+     *
+     * @param {string|Buffer} chunk - A chunk to be transformed.
+     * @param {string} encoding - The encoding of the chunk.
+     * @param {function} callback - A callback function that is called when done.
+     * @returns {void}
+     */
+    _transform(chunk, encoding, callback) {
+        const prefix = this.prefix;
+        const nPrefix = `\n${prefix}`;
+        const state = this.state;
+        const firstPrefix =
+            state.lastIsLinebreak ? prefix :
+            (state.lastPrefix !== prefix) ? "\n" :
+            /* otherwise */ "";
+        const prefixed = `${firstPrefix}${chunk}`.replace(ALL_BR, nPrefix);
+        const index = prefixed.indexOf(prefix, Math.max(0, prefixed.length - prefix.length));
+
+        state.lastPrefix = prefix;
+        state.lastIsLinebreak = (index !== -1);
+
+        callback(null, (index !== -1) ? prefixed.slice(0, index) : prefixed);
+    }
+}
+
+//------------------------------------------------------------------------------
+// Public API
+//------------------------------------------------------------------------------
+
+/**
+ * Create a transform stream to insert the specific prefix.
+ *
+ * Several streams can exist for the same output stream.
+ * This stream will insert the prefix if the last output came from other instance.
+ * To do that, this stream is using a shared state object.
+ *
+ * @param {string} prefix - A prefix text to be inserted.
+ * @param {object} state - A state object.
+ * @param {string} state.lastPrefix - The last prefix which is printed.
+ * @param {boolean} state.lastIsLinebreak -The flag to check whether the last output is a line break or not.
+ * @returns {stream.Transform} The created transform stream.
+ */
+export default function createPrefixTransform(prefix, state) {
+    return new PrefixTransform(prefix, state);
+}

src/lib/npm-run-all.js

@@ -46,6 +46,17 @@ function toOverwriteOptions(config) {
     return options;
 }
 
+/**
+ * Gets the maximum length.
+ *
+ * @param {number} length - The current maximum length.
+ * @param {string} name - A name.
+ * @returns {number} The maximum length.
+ */
+function maxLength(length, name) {
+    return Math.max(name.length, length);
+}
+
 /**
  * Runs npm-scripts which are matched with given patterns.
  *
@@ -90,6 +101,9 @@ function toOverwriteOptions(config) {
  * @param {boolean} options.continueOnError -
  *   The flag to ignore errors.
  *   Default is `false`.
+ * @param {boolean} options.printLabel -
+ *   The flag to print task names at the head of each line.
+ *   Default is `false`.
  * @returns {Promise}
  *   A promise object which becomes fullfilled when all npm-scripts are completed.
  */
@@ -103,7 +117,8 @@ export default function npmRunAll(
         taskList = null,
         packageConfig = null,
         silent = false,
-        continueOnError = false
+        continueOnError = false,
+        printLabel = false
     } = {}
 ) {
     try {
@@ -124,8 +139,21 @@ export default function npmRunAll(
         }
 
         const tasks = matchTasks(taskList || readTasks(), patterns);
+        const labelWidth = tasks.reduce(maxLength, 0);
         const runTasks = parallel ? runTasksInParallel : runTasksInSequencial;
-        return runTasks(tasks, stdin, stdout, stderr, prefixOptions, continueOnError);
+        return runTasks(tasks, {
+            stdin,
+            stdout,
+            stderr,
+            prefixOptions,
+            continueOnError,
+            labelState: {
+                enabled: printLabel,
+                width: labelWidth,
+                lastPrefix: null,
+                lastIsLinebreak: true
+            }
+        });
     }
     catch (err) {
         return Promise.reject(new Error(err.message));

src/lib/run-task.js

@@ -3,9 +3,55 @@
  * @copyright 2015 Toru Nagashima. All rights reserved.
  * See LICENSE file in root directory for full license.
  */
+
+//------------------------------------------------------------------------------
+// Requirements
+//------------------------------------------------------------------------------
+
+import chalk from "chalk";
 import {parse as parseArgs} from "shell-quote";
+import padEnd from "string.prototype.padend";
+import createPrefixTransform from "./create-prefix-transform-stream";
 import spawn from "./spawn";
 
+//------------------------------------------------------------------------------
+// Helpers
+//------------------------------------------------------------------------------
+
+/**
+ * Pass through the argument.
+ *
+ * @param {string} s - An argument.
+ * @returns {string} The argument.
+ */
+function identity(s) {
+    return s;
+}
+
+/**
+ * Wraps stdout/stderr with a transform stream to add the task name as prefix.
+ *
+ * @param {string} taskName - The task name.
+ * @param {stream.Writable} source - An output stream to be wrapped.
+ * @param {stream.Writable} std - process.stdout/process.stderr.
+ * @param {object} labelState - An label state for the transform stream.
+ * @returns {stream.Writable} `source` or the created wrapped stream.
+ */
+function wrapLabeling(taskName, source, std, labelState) {
+    if (source == null || !labelState.enabled) {
+        return source;
+    }
+
+    const label = padEnd(taskName, labelState.width);
+    const color = (source === std) ? chalk.gray : identity;
+    const prefix = color(`[${label}] `);
+    const stream = createPrefixTransform(prefix, labelState);
+
+    stream.pipe(source);
+
+    return stream;
+}
+
 /**
  * Converts a given stream to an option for `child_process.spawn`.
  *
@@ -22,37 +68,54 @@ function detectStreamKind(stream, std) {
     );
 }
 
+//------------------------------------------------------------------------------
+// Interface
+//------------------------------------------------------------------------------
+
 /**
  * Run a npm-script of a given name.
  * The return value is a promise which has an extra method: `abort()`.
  * The `abort()` kills the child process to run the npm-script.
  *
  * @param {string} task - A npm-script name to run.
- * @param {stream.Readable|null} stdin -
+ * @param {object} options - An option object.
+ * @param {stream.Readable|null} options.stdin -
  *   A readable stream to send messages to stdin of child process.
  *   If this is `null`, ignores it.
  *   If this is `process.stdin`, inherits it.
  *   Otherwise, makes a pipe.
- * @param {stream.Writable|null} stdout -
+ * @param {stream.Writable|null} options.stdout -
  *   A writable stream to receive messages from stdout of child process.
  *   If this is `null`, cannot send.
  *   If this is `process.stdout`, inherits it.
  *   Otherwise, makes a pipe.
- * @param {stream.Writable|null} stderr -
+ * @param {stream.Writable|null} options.stderr -
  *   A writable stream to receive messages from stderr of child process.
  *   If this is `null`, cannot send.
  *   If this is `process.stderr`, inherits it.
  *   Otherwise, makes a pipe.
- * @param {string[]} prefixOptions -
+ * @param {string[]} options.prefixOptions -
  *   An array of options which are inserted before the task name.
+ * @param {object} options.labelState - A state object for printing labels.
  * @returns {Promise}
  *   A promise object which becomes fullfilled when the npm-script is completed.
  *   This promise object has an extra method: `abort()`.
  * @private
  */
-export default function runTask(task, stdin, stdout, stderr, prefixOptions) {
+export default function runTask(
+    task,
+    {
+        stdin,
+        stdout: sourceStdout,
+        stderr: sourceStderr,
+        prefixOptions,
+        labelState
+    }
+) {
     let cp = null;
     const promise = new Promise((resolve, reject) => {
+        const stdout = wrapLabeling(task, sourceStdout, process.stdout, labelState);
+        const stderr = wrapLabeling(task, sourceStderr, process.stderr, labelState);
         const stdinKind = detectStreamKind(stdin, process.stdin);
         const stdoutKind = detectStreamKind(stdout, process.stdout);
         const stderrKind = detectStreamKind(stderr, process.stderr);
@@ -66,8 +129,8 @@ export default function runTask(task, stdin, stdout, stderr, prefixOptions) {
 
         // Piping stdio.
         if (stdinKind === "pipe") { stdin.pipe(cp.stdin); }
-        if (stdoutKind === "pipe") { cp.stdout.pipe(stdout); }
-        if (stderrKind === "pipe") { cp.stderr.pipe(stderr); }
+        if (stdoutKind === "pipe") { cp.stdout.pipe(stdout, {end: false}); }
+        if (stderrKind === "pipe") { cp.stderr.pipe(stderr, {end: false}); }
 
         // Register
         cp.on("error", (err) => {