@ioffice/tslint-config-ioffice

iOffice TypeScript Style Guide

Table of Contents

1. Functions
   1. Unused Parameters
2. Arrow Functions
   1. Use Them
3. Blocks
   1. Braces
   2. Cuddled Elses
4. Whitespace
   1. Spaces
   2. In Braces
5. Commas
   1. Leading Trailing
6. Modules
   1. Use Them
   2. Single Export

Functions

• 1.1 Remove them. To prevent them make sure to use noUnusedParameters in your tsconfig.json file.

  // bad
  function foo(a, b, c) {
    return a + b;
  }
  
  // good
  function foo(a, b) {
    return a + b;
  }
  

⬆ back to top

Arrow Functions

• 2.1 When you must use function expressions (as when passing an anonymous function), use arrow function notation.

  // bad
  [1, 2, 3].map(function (x) {
    const y = x + 1;
    return x * y;
  });
  
  // good
  [1, 2, 3].map((x) => {
    const y = x + 1;
    return x * y;
  });
  

  // good
  [0, null, 1, null, 2].filter(x => x !== null);
  

⬆ back to top

Blocks

• 3.1 Use braces with all multi-line blocks.

  // bad
  if (test)
    return false;
  
  // good
  if (test) return false;
  
  // good
  if (test) {
    return false;
  }
  
  // bad
  function foo() { return false; }
  
  // good
  function bar() {
    return false;
  }
  

• 3.2 If you're using multi-line blocks with if and else, put else on the same line as your if block's closing brace.

  // bad
  if (test) {
    thing1();
    thing2();
  }
  else {
    thing3();
  }
  
  // good
  if (test) {
    thing1();
    thing2();
  } else {
    thing3();
  }
  

⬆ back to top

Whitespace

• 4.1 Use soft tabs set to 2 spaces.

  // bad
  function foo() {
      const name;
  }
  
  // bad
  function bar() {
   const name;
  }
  
  // good
  function baz() {
    const name;
  }
  

• 4.2 Add spaces inside curly braces.

  // bad
  const foo = {clark: 'kent'};
  
  // good
  const foo = { clark: 'kent' };
  

⬆ back to top

Commas

• 5.1 Leading commas: Nope.

  // bad
  const story = [
    once
    , upon
    , aTime
  ];
  
  // good
  const story = [
    once,
    upon,
    aTime,
  ];
  
  // bad
  const hero = {
    firstName: 'Ada'
    , lastName: 'Lovelace'
    , birthYear: 1815
    , superPower: 'computers'
  };
  
  // good
  const hero = {
    firstName: 'Ada',
    lastName: 'Lovelace',
    birthYear: 1815,
    superPower: 'computers',
  };
  

⬆ back to top

Modules

• 6.1 Always use modules (import/export) over a non-standard module system. You can always transpile to your preferred module system.

  // bad
  const iOfficeStyleGuide = require('./iOfficeStyleGuide');
  module.exports = iOfficeStyleGuide.ts;
  
  // ok
  import * as iOfficeStyleGuide from './iOfficeStyleGuide';
  const ts = iOfficeStyleGuide.ts;
  export {
    ts,
  };
  
  // best
  import { ts } from './iOfficeStyleGuide';
  export {
    ts,
  };
  

• 6.2 Do not use default exports. Use a single named export which declares all the classes, functions, objects and interfaces that the module is exporting.

  // bad
  export class A {}
  export class B {}
  export default A;
  
  // good
  class C {}
  class D {}
  export {
    C,
    D,
  };
  

  // bad
  export default function() {
  }
  
  // good
  function A() {
  }
  export { A };
  

  // good
  function A() {
  }
  export { A };
  

⬆ back to top