feat(cli): add config and yes options

- Allow generator options to be passed in json format from
  a file, stdin, or stringified value
- Allow prompts to be skipped if a prompt has default value or
  the corresponding anwser exists in options

docs/site/includes/CLI-std-options.md

@@ -10,4 +10,21 @@
 
 `--skip-install`
 : Do not automatically install dependencies. Default is false.
+
+`-c, --config`
+: JSON file name or value to configure options
+
+For example,
+```sh
+lb4 app --config config.json
+lb4 app --config {"name":"my-app"}
+cat config.json | lb4 app --config stdin
+lb4 app --config stdin < config.json
+lb4 app --config stdin << EOF
+> {"name":"my-app"}
+> EOF
+```
+
+`-y, --yes`
+: Skip all confirmation prompts with default or provided value
 <!-- prettier-ignore-end -->

packages/cli/generators/controller/index.js

@@ -28,6 +28,7 @@ module.exports = class ControllerGenerator extends ArtifactGenerator {
   }
 
   _setupGenerator() {
+    super._setupGenerator();
     this.artifactInfo = {
       type: 'controller',
       rootDir: 'src',
@@ -54,8 +55,10 @@ module.exports = class ControllerGenerator extends ArtifactGenerator {
       required: false,
       description: 'Type for the ' + this.artifactInfo.type,
     });
+  }
 
-    return super._setupGenerator();
+  setOptions() {
+    return super.setOptions();
   }
 
   checkLoopBackProject() {

packages/cli/generators/datasource/index.js

@@ -60,6 +60,10 @@ module.exports = class DataSourceGenerator extends ArtifactGenerator {
     return super._setupGenerator();
   }
 
+  setOptions() {
+    return super.setOptions();
+  }
+
   /**
    * Ensure CLI is being run in a LoopBack 4 project.
    */

packages/cli/lib/artifact-generator.js

@@ -19,23 +19,27 @@ module.exports = class ArtifactGenerator extends BaseGenerator {
 
   _setupGenerator() {
     debug('Setting up generator');
+    super._setupGenerator();
     this.argument('name', {
       type: String,
       required: false,
       description: 'Name for the ' + this.artifactInfo.type,
     });
+  }
+
+  setOptions() {
     // argument validation
-    if (this.args.length) {
-      const validationMsg = utils.validateClassName(this.args[0]);
+    const name = this.options.name;
+    if (name) {
+      const validationMsg = utils.validateClassName(name);
       if (typeof validationMsg === 'string') throw new Error(validationMsg);
     }
-    this.artifactInfo.name = this.args[0];
-    this.artifactInfo.defaultName = 'new';
+    this.artifactInfo.name = name;
     this.artifactInfo.relPath = path.relative(
       this.destinationPath(),
       this.artifactInfo.outDir,
     );
-    super._setupGenerator();
+    return super.setOptions();
   }
 
   promptArtifactName() {
@@ -48,6 +52,7 @@ module.exports = class ArtifactGenerator extends BaseGenerator {
         // capitalization
         message: utils.toClassName(this.artifactInfo.type) + ' class name:',
         when: this.artifactInfo.name === undefined,
+        default: this.artifactInfo.name,
         validate: utils.validateClassName,
       },
     ];

packages/cli/lib/base-generator.js

@@ -7,9 +7,13 @@
 
 const Generator = require('yeoman-generator');
 const chalk = require('chalk');
-const debug = require('./debug')('artifact-generator');
 const utils = require('./utils');
 const StatusConflicter = utils.StatusConflicter;
+const path = require('path');
+const fs = require('fs');
+const readline = require('readline');
+const debug = require('./debug')('base-generator');
+
 /**
  * Base Generator for LoopBack 4
  */
@@ -28,11 +32,235 @@ module.exports = class BaseGenerator extends Generator {
    * Subclasses can extend _setupGenerator() to set up the generator
    */
   _setupGenerator() {
+    this.option('config', {
+      type: String,
+      alias: 'c',
+      description: 'JSON file name or value to configure options',
+    });
+
+    this.option('yes', {
+      type: Boolean,
+      alias: 'y',
+      description:
+        'Skip all confirmation prompts with default or provided value',
+    });
+
     this.artifactInfo = this.artifactInfo || {
       rootDir: 'src',
     };
   }
 
+  /**
+   * Read a json document from stdin
+   */
+  _readJSONFromStdin() {
+    const rl = readline.createInterface({
+      input: process.stdin,
+    });
+
+    const lines = [];
+    if (process.stdin.isTTY) {
+      this.log(
+        chalk.green(
+          'Please type in a json object line by line ' +
+            '(Press <ctrl>-D or type EOF to end):',
+        ),
+      );
+    }
+
+    let err;
+    return new Promise((resolve, reject) => {
+      rl.on('SIGINT', () => {
+        err = new Error('Canceled by user');
+        rl.close();
+        reject(err);
+      })
+        .on('line', line => {
+          if (line === 'EOF') {
+            rl.close();
+          } else {
+            lines.push(line);
+          }
+        })
+        .on('close', () => {
+          if (err) return;
+          const jsonStr = lines.join('\n');
+          try {
+            const json = JSON.parse(jsonStr);
+            resolve(json);
+          } catch (e) {
+            if (!process.stdin.isTTY) {
+              debug(e, jsonStr);
+            }
+            reject(e);
+          }
+        })
+        .on('error', e => {
+          err = e;
+          rl.close();
+          reject(err);
+        });
+    });
+  }
+
+  async setOptions() {
+    let opts = {};
+    const jsonFileOrValue = this.options.config;
+    try {
+      if (jsonFileOrValue === 'stdin' || !process.stdin.isTTY) {
+        this.options['yes'] = true;
+        opts = await this._readJSONFromStdin();
+      } else if (typeof jsonFileOrValue === 'string') {
+        const jsonFile = path.resolve(process.cwd(), jsonFileOrValue);
+        if (fs.existsSync(jsonFile)) {
+          opts = this.fs.readJSON(jsonFile);
+        } else {
+          // Try parse the config as stringified json
+          opts = JSON.parse(jsonFileOrValue);
+        }
+      }
+    } catch (e) {
+      this.exit(e);
+      return;
+    }
+    if (typeof opts !== 'object') {
+      this.exit('Invalid config file or value: ' + jsonFileOrValue);
+      return;
+    }
+    for (const o in opts) {
+      if (this.options[o] == null) {
+        this.options[o] = opts[o];
+      }
+    }
+  }
+
+  /**
+   * Check if a question can be skipped in `express` mode
+   * @param {object} question A yeoman prompt
+   */
+  _isQuestionOptional(question) {
+    return (
+      question.default != null || // Having a default value
+      this.options[question.name] != null || // Configured in options
+      question.type === 'list' || // A list
+      question.type === 'rawList' || // A raw list
+      question.type === 'checkbox' || // A checkbox
+      question.type === 'confirm'
+    ); // A confirmation
+  }
+
+  /**
+   * Get the default answer for a question
+   * @param {*} question
+   */
+  async _getDefaultAnswer(question, answers) {
+    let def = question.default;
+    if (typeof question.default === 'function') {
+      def = await question.default(answers);
+    }
+    let defaultVal = def;
+
+    if (def == null) {
+      // No `default` is set for the question, check existing answers
+      defaultVal = answers[question.name];
+      if (defaultVal != null) return defaultVal;
+    }
+
+    if (question.type === 'confirm') {
+      return defaultVal != null ? defaultVal : true;
+    }
+    if (question.type === 'list' || question.type === 'rawList') {
+      // Default to 1st item
+      if (def == null) def = 0;
+      if (typeof def === 'number') {
+        // The `default` is an index
+        const choice = question.choices[def];
+        if (choice) {
+          defaultVal = choice.value || choice.name;
+        }
+      } else {
+        // The default is a value
+        if (question.choices.map(c => c.value || c.name).includes(def)) {
+          defaultVal = def;
+        }
+      }
+    } else if (question.type === 'checkbox') {
+      if (def == null) {
+        defaultVal = question.choices
+          .filter(c => c.checked && !c.disabled)
+          .map(c => c.value || c.name);
+      } else {
+        defaultVal = def
+          .map(d => {
+            if (typeof d === 'number') {
+              const choice = question.choices[d];
+              if (choice && !choice.disabled) {
+                return choice.value || choice.name;
+              }
+            } else {
+              if (
+                question.choices.find(
+                  c => !c.disabled && d === (c.value || c.name),
+                )
+              ) {
+                return d;
+              }
+            }
+            return undefined;
+          })
+          .filter(v => v != null);
+      }
+    }
+    return defaultVal;
+  }
+
+  /**
+   * Override the base prompt to skip prompts with default answers
+   * @param questions One or more questions
+   */
+  async prompt(questions) {
+    // Normalize the questions to be an array
+    if (!Array.isArray(questions)) {
+      questions = [questions];
+    }
+    if (!this.options['yes']) {
+      if (!process.stdin.isTTY) {
+        this.log(
+          chalk.red('The stdin is not a terminal. No prompt is allowed.'),
+        );
+        process.exit(1);
+      }
+      // Non-express mode, continue to prompt
+      return await super.prompt(questions);
+    }
+
+    const answers = Object.assign({}, this.options);
+
+    for (const q of questions) {
+      let when = q.when;
+      if (typeof when === 'function') {
+        when = await q.when(answers);
+      }
+      if (when === false) continue;
+      if (this._isQuestionOptional(q)) {
+        const answer = await this._getDefaultAnswer(q, answers);
+        debug('%s: %j', q.name, answer);
+        answers[q.name] = answer;
+      } else {
+        if (!process.stdin.isTTY) {
+          this.log(
+            chalk.red('The stdin is not a terminal. No prompt is allowed.'),
+          );
+          process.exit(1);
+        }
+        // Only prompt for non-skipped questions
+        const props = await super.prompt([q]);
+        Object.assign(answers, props);
+      }
+    }
+    return answers;
+  }
+
   /**
    * Override the usage text by replacing `yo loopback4:` with `lb4 `.
    */
@@ -96,6 +324,7 @@ module.exports = class BaseGenerator extends Generator {
    */
   end() {
     if (this.shouldExit()) {
+      debug(this.exitGeneration);
       this.log(chalk.red('Generation is aborted:', this.exitGeneration));
       return false;
     }

packages/cli/lib/project-generator.js

@@ -82,7 +82,9 @@ module.exports = class ProjectGenerator extends BaseGenerator {
     this.registerTransformStream(utils.renameEJS());
   }
 
-  setOptions() {
+  async setOptions() {
+    await super.setOptions();
+    if (this.shouldExit()) return false;
     if (this.options.name) {
       const msg = utils.validate(this.options.name);
       if (typeof msg === 'string') {
@@ -148,6 +150,7 @@ module.exports = class ProjectGenerator extends BaseGenerator {
 
     return this.prompt(prompts).then(props => {
       Object.assign(this.projectInfo, props);
+      this.destinationRoot(this.projectInfo.outdir);
     });
   }
 
@@ -187,7 +190,6 @@ module.exports = class ProjectGenerator extends BaseGenerator {
 
   scaffold() {
     if (this.shouldExit()) return false;
-    this.destinationRoot(this.projectInfo.outdir);
 
     // First copy common files from ../../project/templates
     this.fs.copyTpl(

packages/cli/package.json

@@ -31,6 +31,7 @@
     "glob": "^7.1.2",
     "mem-fs": "^1.1.3",
     "mem-fs-editor": "^4.0.0",
+    "mock-stdin": "^0.3.1",
     "nsp": "^3.2.1",
     "request": "^2.87.0",
     "request-promise-native": "^1.0.5",