• Make sure it passes the linter

  npm run check
  

  Will run eslint

  And the tests

  npm test
  

• JavaScript style

  In general.

  • variable declaration

    One per line

    var a;  // good
    var b;
    
    var a, b;  // bad
    

*   braces

    k&r style

        if (cond) {   // good
           ...code..
        }

        if (cond) { ..code.. } // bad
        if (cond)
        {
             // bad
        }

*   use `===`

        if (a === b) {  // good
        if (a !== b) {  // good
        if (a == b)  {  // bad
        if (a != b)  {  // bad

*   use `v = option || default` when appropriate

        function(width) {
           width = width || 300; // good

        function(width) {
           width = (width !== undefined) ? width : 300;  // bad

    Of course use good judgement. Sometimes the second form is more appropriate

*   use positive options

        options.autoResize    // good
        options.dontResize    // bad

    If the default is for the options to be `true` then make check that check for
    undefined

        var autoResize = options.autoResize === undefined ? true : options.autoResize;

*   naming

        someVariable;
        SomeClass;
        someFunction;

*   loops

    prefer forEach

        someArray.forEach(... // good
        Object(someObject).keys().forEach(... // good

        for (var ndx = 0; ndx < someArray.length; ++ndx)  // ok if neded

        for (var key in someObject)  // bad

    Yes I know that other methods might be faster today. First off we're not processing
    a million things so the perf doens't matter. Second JS gets faster and this is
    the form most work will be spent on optimizing since it's the language's preferred
    way of iterating.

*   trailing commas

        var someObj = {
           prop1: value1,
           prop2: value2,
           prop3: value3,   // good
        };

       var someObj = {
          prop1: value1,
          prop2: value2,
          prop3: value3     // bad
       };