js.md

_* This rule is not the best practice but the one that we (developers at ownego) think is most suited for better software development.

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RESOURCE

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Airbnb style guide: see here

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SOME COMMON RULES

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Highly recommend reading full airbnb guide. Below is just some common rules that are extracted from that guide.

1- Do not use new keyword. Use literal syntax instead.

// Not good
var newObj = new Object();
var newArr = new Array();

// Good
var newObj = {};
var newArr = [];

2- Copy Array or Object. Be careful when working with Array or Object. If you use normal assignment or shallow copy, you only work on a reference to original value.

• Array:

  • Shallow copy: use javascript function slice(). See here. (jQuery.extend() is ok too)

  var srcArr = ['abc', 'def', 'ghi'];
  var destArr = srcArr.slice();
  
  console.log(destArr);
  
  // output
  // ['abc', 'def', 'ghi']
  

  • Deep copy: use jQuery.extend(). See example below.

• Object: For both shallow and deep copy use jQuery.extend() or write your own function (not recommend). More details

  var srcObj = {
    apple: 0,
    banana: {
      price: 50,
      weight: 10
    },
    cherry: 100
  };
  var destObj = $.extend({}, srcObj);
  
  console.log(destObj);
  
  // output
  // Object destObj
  // {
  //   apple: 0,
  //   banana: {
  //     price: 50,
  //     weight: 10
  //   },
  //   cherry: 100
  // }
  

3- Use Array.push().

var arr = [];

// Not good
arr[arr.length] = 'someValue';

// Good
arr.push('someValue');

4- Use one var for each variable.

Advantage:

• Easier when add/remove a variable
• No need to worry about , or ;
• Easy to convert to es6

Also avoid unassigned variable declaration.

5- Comparison and Equality See here

6- Conditional statements format

// if/else
if (condition) {
  // do something
} else if (another condition) {
  // do something
} ... {
  // some stuff
} else {
  // do something
}

// switch
switch (srcTarget) {
  case value1:
    // do something
    break;
  ...
  default:
    // do something
}