Adds a NumberPrompt type for convenience (#654)

lib/inquirer.js

@@ -54,6 +54,7 @@ inquirer.createPromptModule = function(opt) {
   promptModule.restoreDefaultPrompts = function() {
     this.registerPrompt('list', require('./prompts/list'));
     this.registerPrompt('input', require('./prompts/input'));
+    this.registerPrompt('number', require('./prompts/number'));
     this.registerPrompt('confirm', require('./prompts/confirm'));
     this.registerPrompt('rawlist', require('./prompts/rawlist'));
     this.registerPrompt('expand', require('./prompts/expand'));

lib/prompts/number.js

@@ -0,0 +1,28 @@
+'use strict';
+/**
+ * `input` type prompt
+ */
+
+var Input = require('./input');
+
+/**
+ * Extention of the Input prompt specifically for use with number inputs.
+ */
+
+class NumberPrompt extends Input {
+  filterInput(input) {
+    if (input && typeof input === 'string') {
+      input = input.trim();
+      // Match a number in the input
+      let numberMatch = input.match(/(^-?\d+|^\d+\.\d*|^\d*\.\d+)(e\d+)?$/);
+      // If a number is found, return that input.
+      if (numberMatch) {
+        return Number(numberMatch[0]);
+      }
+    }
+    // If the input was invalid return the default value.
+    return this.opt.default == null ? NaN : this.opt.default;
+  }
+}
+
+module.exports = NumberPrompt;

test/helpers/fixtures.js

@@ -6,6 +6,11 @@ module.exports = {
     name: 'name'
   },
 
+  number: {
+    message: 'message',
+    name: 'name'
+  },
+
   confirm: {
     message: 'message',
     name: 'name'

test/specs/prompts/number.js

@@ -0,0 +1,116 @@
+var expect = require('chai').expect;
+var _ = require('lodash');
+var ReadlineStub = require('../../helpers/readline');
+var fixtures = require('../../helpers/fixtures');
+
+var NumberPrompt = require('../../../lib/prompts/number');
+
+const ACCEPTABLE_ERROR = 0.001;
+
+describe('`number` prompt', function() {
+  beforeEach(function() {
+    this.fixture = _.clone(fixtures.number);
+    this.rl = new ReadlineStub();
+    this.number = new NumberPrompt(this.fixture, this.rl);
+  });
+
+  it('should parse the largest number', function(done) {
+    this.number.run().then(answer => {
+      expect(answer).to.equal(Number.MAX_SAFE_INTEGER);
+      done();
+    });
+
+    this.rl.emit('line', String(Number.MAX_SAFE_INTEGER));
+  });
+
+  it('should parse the smallest number', function(done) {
+    this.number.run().then(answer => {
+      expect(answer).to.equal(Number.MIN_SAFE_INTEGER);
+      done();
+    });
+
+    this.rl.emit('line', String(Number.MIN_SAFE_INTEGER));
+  });
+
+  it('should parse an integer', function(done) {
+    this.number.run().then(answer => {
+      expect(answer).to.equal(42);
+      done();
+    });
+
+    this.rl.emit('line', '42');
+  });
+
+  it('should parse negative numbers', function(done) {
+    this.number.run().then(answer => {
+      expect(answer).to.equal(-363);
+      done();
+    });
+
+    this.rl.emit('line', '-363');
+  });
+
+  it('should parse a regular float', function(done) {
+    this.number.run().then(answer => {
+      expect(answer).to.be.closeTo(4353.43, ACCEPTABLE_ERROR);
+      done();
+    });
+
+    this.rl.emit('line', '4353.43');
+  });
+
+  it('should parse a float with no digits before the decimal', function(done) {
+    this.number.run().then(answer => {
+      expect(answer).to.be.closeTo(0.01264, ACCEPTABLE_ERROR);
+      done();
+    });
+
+    this.rl.emit('line', '.01264');
+  });
+
+  it('should parse a float with no digits after the decimal', function(done) {
+    this.number.run().then(answer => {
+      expect(answer).to.be.closeTo(1234.0, ACCEPTABLE_ERROR);
+      done();
+    });
+
+    this.rl.emit('line', '1234.');
+  });
+
+  it('should parse a float with exponents', function(done) {
+    this.number.run().then(answer => {
+      expect(answer).to.be.closeTo(534e12, ACCEPTABLE_ERROR);
+      done();
+    });
+
+    this.rl.emit('line', '534e12');
+  });
+
+  it('should parse any other string as NaN', function(done) {
+    this.number.run().then(answer => {
+      expect(answer).to.be.NaN; // eslint-disable-line no-unused-expressions
+      done();
+    });
+
+    this.rl.emit('line', 'The cat');
+  });
+
+  it('should parse the empty string as NaN', function(done) {
+    this.number.run().then(answer => {
+      expect(answer).to.be.NaN; // eslint-disable-line no-unused-expressions
+      done();
+    });
+
+    this.rl.emit('line', '');
+  });
+
+  it('should return default value if it is set on a bad input', function(done) {
+    this.number.opt.default = 11;
+    this.number.run().then(answer => {
+      expect(answer).to.equal(11);
+      done();
+    });
+
+    this.rl.emit('line', '');
+  });
+});