Merge pull request #4586 from serverless/add-levenshtein

Add "did you mean..." suggestions when you make a typo

lib/classes/CLI.js

@@ -5,6 +5,7 @@ const minimist = require('minimist');
 const _ = require('lodash');
 const os = require('os');
 const chalk = require('chalk');
+const getCommandSuggestion = require('../utils/getCommandSuggestion');
 
 class CLI {
   constructor(serverless, inputArray) {
@@ -149,7 +150,6 @@ class CLI {
     this.consoleLog(chalk.dim('* Documentation: https://serverless.com/framework/docs/'));
 
     this.consoleLog('');
-
     if (!_.isEmpty(frameworkCommands)) {
       _.forEach(frameworkCommands, (details, command) => {
         this.displayCommandUsage(details, command);
@@ -252,8 +252,9 @@ class CLI {
 
     // Throw error if command not found.
     if (!command) {
+      const suggestedCommand = getCommandSuggestion(commandName, allCommands);
       const errorMessage = [
-        `Serverless command "${commandName}" not found.`,
+        `Serverless command "${commandName}" not found. Did you mean "${suggestedCommand}"?`,
         ' Run "serverless help" for a list of all available commands.',
       ].join('');
       throw new this.serverless.classes.Error(errorMessage);
@@ -266,6 +267,7 @@ class CLI {
     this.displayCommandOptions(command);
 
     this.consoleLog('');
+    return null;
   }
 
   getVersionNumber() {

lib/classes/PluginManager.js

@@ -8,6 +8,7 @@ const writeFile = require('../utils/fs/writeFile');
 const getCacheFilePath = require('../utils/getCacheFilePath');
 const getServerlessConfigFile = require('../utils/getServerlessConfigFile');
 const crypto = require('crypto');
+const getCommandSuggestion = require('../utils/getCommandSuggestion');
 
 /**
  * @private
@@ -324,9 +325,12 @@ class PluginManager {
         return current.commands[name];
       }
       const commandName = commandOrAlias.slice(0, index + 1).join(' ');
-      const errorMessage = `Serverless command "${commandName}" not found
-
-  Run "serverless help" for a list of all available commands.`;
+      const suggestedCommand = getCommandSuggestion(commandName,
+        this.serverless.cli.loadedCommands);
+      const errorMessage = [
+        `Serverless command "${commandName}" not found. Did you mean "${suggestedCommand}"?`,
+        ' Run "serverless help" for a list of all available commands.',
+      ].join('');
       throw new this.serverless.classes.Error(errorMessage);
     }, { commands: this.commands });
   }

lib/utils/getCommandSuggestion.js

@@ -0,0 +1,36 @@
+'use strict';
+const _ = require('lodash');
+const levenshtein = require('fast-levenshtein');
+
+const getCollectCommandWords = (commandObject, commandWordsArray) => {
+  let wordsArray = _.isArray(commandWordsArray)
+    && !_.isEmpty(commandWordsArray) ? commandWordsArray : [];
+  _.forEach(commandObject, (commandChildObject, commandChildName) => {
+    wordsArray.push(commandChildName);
+    if (commandChildObject.commands) {
+      wordsArray = getCollectCommandWords(commandChildObject.commands, wordsArray);
+    }
+  });
+  return _.uniq(wordsArray);
+};
+
+const getCommandSuggestion = (inputCommand, allCommandsObject) => {
+  let suggestion;
+  const commandWordsArray = getCollectCommandWords(allCommandsObject);
+  let minValue = 0;
+  _.forEach(commandWordsArray, correctCommand => {
+    const distance = levenshtein.get(inputCommand, correctCommand);
+    if (minValue === 0) {
+      suggestion = correctCommand;
+      minValue = distance;
+    }
+
+    if (minValue > distance) {
+      suggestion = correctCommand;
+      minValue = distance;
+    }
+  });
+  return suggestion;
+};
+
+module.exports = getCommandSuggestion;

lib/utils/getCommandSuggestion.test.js

@@ -0,0 +1,25 @@
+'use strict';
+
+const expect = require('chai').expect;
+const getCommandSuggestion = require('./getCommandSuggestion');
+const Serverless = require('../../lib/Serverless');
+
+const serverless = new Serverless();
+serverless.init();
+
+describe('#getCommandSuggestion', () => {
+  it('should return "package" as a suggested command if you input "pekage"', () => {
+    const suggestedCommand = getCommandSuggestion('pekage', serverless.cli.loadedCommands);
+    expect(suggestedCommand).to.be.equal('package');
+  });
+
+  it('should return "deploy" as a suggested command if you input "deploi"', () => {
+    const suggestedCommand = getCommandSuggestion('deploi', serverless.cli.loadedCommands);
+    expect(suggestedCommand).to.be.equal('deploy');
+  });
+
+  it('should return "invoke" as a suggested command if you input "lnvoke"', () => {
+    const suggestedCommand = getCommandSuggestion('lnvoke', serverless.cli.loadedCommands);
+    expect(suggestedCommand).to.be.equal('invoke');
+  });
+});

package.json

@@ -100,6 +100,7 @@
     "chalk": "^2.0.0",
     "ci-info": "^1.1.1",
     "download": "^5.0.2",
+    "fast-levenshtein": "^2.0.6",
     "filesize": "^3.3.0",
     "fs-extra": "^0.26.7",
     "get-stdin": "^5.0.1",