feat: avoid adding multiple lines to SHELL scripts

lib/installer.js

@@ -8,12 +8,26 @@ const readFile = promisify(fs.readFile);
 const writeFile = promisify(fs.writeFile);
 const { BASH_LOCATION, FISH_LOCATION, ZSH_LOCATION } = require('./constants');
 
+/**
+ * Little helper to return the correct file extension based on the SHELL script
+ * location.
+ *
+ * @param {String} location - Shell script location
+ * @returns The correct file extension for the given SHELL script location
+ */
 const shellExtension = location => {
   if (location === BASH_LOCATION) return 'bash';
   if (location === FISH_LOCATION) return 'fish';
   if (location === ZSH_LOCATION) return 'zsh';
 };
 
+/**
+ * Helper to return the correct script template based on the SHELL script
+ * location
+ *
+ * @param {String} location - Shell script location
+ * @returns The template script content
+ */
 const scriptFromLocation = location => {
   if (location === BASH_LOCATION) {
     return path.join(__dirname, '../scripts/bash.sh');
@@ -28,38 +42,165 @@ const scriptFromLocation = location => {
   }
 };
 
-const writeToShellConfig = ({ name, location }) => {
-  debug(`Adding tabtab script to ${location}`);
-  const filename = path.join(
+/**
+ * Checks a given file for the existence of a specific line. Used to prevent
+ * adding multiple completion source to SHELL scripts.
+ *
+ * @param {String} filename - The filename to check against
+ * @param {String} line     - The line to look for
+ * @returns {Boolean} true or false, false if the line is not present.
+ */
+const checkFilenameForLine = async (filename, line) => {
+  debug('Check filename (%s) for "%s"', filename, line);
+
+  let filecontent = '';
+  try {
+    filecontent = await readFile(untildify(filename), 'utf8');
+  } catch (err) {
+    if (err.code !== 'ENOENT') {
+      return console.error(
+        'Got an error while trying to read from %s file',
+        filename,
+        err
+      );
+    }
+  }
+
+  return !!filecontent.match(`\n${line}\n`);
+};
+
+/**
+ * Opens a file for modification adding a new `source` line for the given
+ * SHELL. Used for both SHELL script and tabtab internal one.
+ *
+ * @param {Object} options - Options with
+ *    - filename: The file to modify
+ *    - scriptname: The line to add sourcing this file
+ *    - location: The SHELL script location
+ *    - name: The package being configured
+ *    - inShellConfig: Whether it is done in the SHELL script location, used to
+ *    add a few more descriptive lines to the file
+ */
+const writeLineToFilename = ({
+  filename,
+  scriptname,
+  location,
+  name,
+  inShellConfig
+}) => (resolve, reject) => {
+  const stream = fs.createWriteStream(untildify(filename), { flags: 'a' });
+  stream.on('error', reject);
+  stream.on('finish', () => resolve());
+
+  debug('Writing to shell configuration file (%s)', filename);
+  debug('scriptname:', scriptname);
+
+  if (inShellConfig) {
+    stream.write(`\n# tabtab source for completion packages`);
+    stream.write('\n# uninstall by removing these lines');
+  } else {
+    stream.write(`\n# tabtab source for ${name} package`);
+  }
+
+  if (location === BASH_LOCATION) {
+    stream.write(`\n[ -f ${scriptname} ] && . ${scriptname} || true`);
+  } else if (location === FISH_LOCATION) {
+    debug('Addding fish line');
+    stream.write(`\n[ -f ${scriptname} ]; and . ${scriptname}; or true`);
+  } else if (location === ZSH_LOCATION) {
+    debug('Addding zsh line');
+    stream.write(`\n[[ -f ${scriptname} ]] && . ${scriptname} || true`);
+  }
+
+  stream.end('\n');
+};
+
+/**
+ * Writes to SHELL config file adding a new line, but only one, to the SHELL
+ * config script. This enables tabtab to work for the given SHELL.
+ *
+ * @param {Object} options - Options object with
+ *    - location: The SHELL script location (~/.bashrc, ~/.zshrc or
+ *    ~/.config/fish/config.fish)
+ *    - name: The package configured for completion
+ */
+const writeToShellConfig = async ({ location, name }) => {
+  const scriptname = path.join(
     __dirname,
     '../.completions',
-    `${name}.${shellExtension(location)}`
+    `__tabtab.${shellExtension(location)}`
   );
-  debug('Which filename', filename);
 
-  return new Promise((resolve, reject) => {
-    const stream = fs.createWriteStream(untildify(location), { flags: 'a' });
-    stream.on('error', reject);
-    stream.on('finish', () => resolve());
+  const filename = location;
 
-    debug('Writing to shell configuration file (%s)', location);
-    stream.write(`\n# tabtab source for ${name} package`);
-    stream.write('\n# uninstall by removing these lines');
+  // Check if SHELL script already has a line for tabtab
+  const existing = await checkFilenameForLine(
+    filename,
+    `# tabtab source for completion packages`
+  );
+  if (existing) {
+    return debug('Tabtab line already exists in %s file', filename);
+  }
 
-    if (location === BASH_LOCATION) {
-      stream.write(`\n[ -f ${filename} ] && . ${filename} || true`);
-    } else if (location === FISH_LOCATION) {
-      debug('Addding fish line');
-      stream.write(`\n[ -f ${filename} ]; and . ${filename}; or true`);
-    } else if (location === ZSH_LOCATION) {
-      debug('Addding zsh line');
-      stream.write(`\n[[ -f ${filename} ]] && . ${filename} || true`);
-    }
+  return new Promise(
+    writeLineToFilename({
+      filename,
+      scriptname,
+      location,
+      name,
+      inShellConfig: true
+    })
+  );
+};
+
+/**
+ * Writes to tabtab internal script that acts as a frontend router for the
+ * completion mechanism, in the internal .completions/ directory. Every
+ * completion is added to this file.
+ *
+ * @param {Object} options - Options object with
+ *    - location: The SHELL script location (~/.bashrc, ~/.zshrc or
+ *    ~/.config/fish/config.fish)
+ *    - name: The package configured for completion
+ */
+const writeToTabtabScript = async ({ name, location }) => {
+  const filename = path.join(
+    __dirname,
+    '../.completions',
+    `__tabtab.${shellExtension(location)}`
+  );
+
+  const scriptname = path.join(
+    __dirname,
+    '../.completions',
+    `${name}.${shellExtension(location)}`
+  );
+
+  // Check if tabtab completion file already has this line in it
+  const existing = await checkFilenameForLine(
+    filename,
+    `# tabtab source for ${name} package`
+  );
+  if (existing) {
+    return debug('Tabtab line already exists in %s file', filename);
+  }
 
-    stream.end('\n');
-  });
+  return new Promise(
+    writeLineToFilename({ filename, scriptname, location, name })
+  );
 };
 
+/**
+ * This writes a new completion script in the internal `.completions/`
+ * directory. Depending on the SHELL used (and the location parameter), a
+ * different script is created for the given SHELL.
+ *
+ * @param {Object} options - Options object with
+ *    - name: The package configured for completion
+ *    - completer: The binary that will act as the completer for `name` program
+ *    - location: The SHELL script location (~/.bashrc, ~/.zshrc or
+ *    ~/.config/fish/config.fish)
+ */
 const writeToCompletionScript = ({ name, completer, location }) => {
   const filename = path.join(
     __dirname,
@@ -82,34 +223,58 @@ const writeToCompletionScript = ({ name, completer, location }) => {
     .then(filecontent => writeFile(filename, filecontent));
 };
 
-const installer = {
-  install(options = { name: '', completer: '', location: '' }) {
-    debug('Install with options', options);
-    if (!options.name) {
-      throw new TypeError('options.name is required');
-    }
+/**
+ * Top level install method. Does three things:
+ *
+ * - Writes to SHELL config file, adding a new line to tabtab internal script.
+ * - Creates or edit tabtab internal script
+ * - Creates the actual completion script for this package.
+ *
+ * @param {Object} options - Options object with
+ *    - name: The program name to complete
+ *    - completer: The actual program or binary that will act as the completer
+ *    for `name` program. Can be the same.
+ *    - location: The SHELL script config location (~/.bashrc, ~/.zshrc or
+ *    ~/.config/fish/config.fish)
+ */
+const install = (options = { name: '', completer: '', location: '' }) => {
+  debug('Install with options', options);
+  if (!options.name) {
+    throw new TypeError('options.name is required');
+  }
 
-    if (!options.completer) {
-      throw new TypeError('options.completer is required');
-    }
+  if (!options.completer) {
+    throw new TypeError('options.completer is required');
+  }
 
-    if (!options.location) {
-      throw new TypeError('options.location is required');
-    }
+  if (!options.location) {
+    throw new TypeError('options.location is required');
+  }
 
-    return Promise.all([
-      writeToShellConfig(options),
-      writeToCompletionScript(options)
-    ]);
-  },
+  return Promise.all([
+    writeToShellConfig(options),
+    writeToTabtabScript(options),
+    writeToCompletionScript(options)
+  ]);
+};
 
-  uninstall(options = { name: '' }) {
-    debug('Uninstall with options', options);
-    throw new Error('Not yet implemented');
-  },
+/**
+ * Not yet implemented. Here the idea is to uninstall a given package
+ * completion from internal tabtab and / or the SHELL config.
+ *
+ * @param {type} name - parameter description...
+ */
+const uninstall = (options = { name: '' }) => {
+  debug('Uninstall with options', options);
+  throw new Error('Not yet implemented');
+};
 
+module.exports = {
+  install,
+  uninstall,
+  checkFilenameForLine,
   writeToShellConfig,
-  writeToCompletionScript
+  writeToTabtabScript,
+  writeToCompletionScript,
+  writeLineToFilename
 };
-
-module.exports = installer;

package.json

@@ -4,7 +4,7 @@
   "description": "tab completion helpers, for node cli programs. Inspired by npm completion.",
   "main": "lib/index.js",
   "scripts": {
-    "test": "DEBUG='tabtab*' TABTAB_DEBUG='./test/tabtab.log' c8 mocha --timeout 5000",
+    "test": "DEBUG='tabtab*' c8 mocha --timeout 5000",
     "posttest": "npm run eslint",
     "mocha": "DEBUG='tabtab*' mocha --timeout 5000",
     "coverage": "c8 report --reporter=text-lcov | coveralls",

test/installer.js

@@ -1,5 +1,6 @@
 const assert = require('assert');
 const fs = require('fs');
+const path = require('path');
 const untildify = require('untildify');
 const { promisify } = require('util');
 const {
@@ -50,8 +51,22 @@ describe('installer', () => {
       })
         .then(() => readFile(untildify('~/.bashrc'), 'utf8'))
         .then(filecontent => {
-          assert.ok(/tabtab source for foo/.test(filecontent));
+          assert.ok(/tabtab source for completion packages/.test(filecontent));
           assert.ok(/uninstall by removing these lines/.test(filecontent));
+          assert.ok(
+            /\[ -f .+__tabtab.bash ] && \. .+tabtab\/.completions\/__tabtab.bash || true/.test(
+              filecontent
+            )
+          );
+        })
+        .then(() =>
+          readFile(
+            path.join(__dirname, '../.completions/__tabtab.bash'),
+            'utf8'
+          )
+        )
+        .then(filecontent => {
+          assert.ok(/tabtab source for foo/.test(filecontent));
           assert.ok(
             /\[ -f .+foo.bash ] && \. .+tabtab\/.completions\/foo.bash || true/.test(
               filecontent

test/tabtab-install.js

@@ -78,7 +78,7 @@ describe('tabtab.install()', () => {
         })
         .then(() => readFile(untildify('~/.bashrc'), 'utf8'))
         .then(filecontent => {
-          assert.ok(/tabtab source for foo/.test(filecontent));
+          assert.ok(/tabtab source for completion packages/.test(filecontent));
           assert.ok(/uninstall by removing these lines/.test(filecontent));
           assert.ok(
             /\[ -f .+foo.bash ] && \. .+tabtab\/.completions\/foo.bash || true/.test(