Coding Guidelines


This provides general coding guidelines for Gawati code. This document covers different programming languages used in Gawati: XQuery (.xql, .xqm), JavaScript (.js), Java (.java). The objective of having guidelines is to keep the code-base consistent and readable which is a critical part keeping the code maintainable and manageable.

Basic Rules across all languages

No mixing of tabs and spaces

The code must use 4 spaces (instead of a tab) for indentation, except for third party libraries (e.g. XSLTforms, YUI). Most modern code editing tools support mapping a tab to 4 spaces. Every logical depth level in the code needs to have an indent. There should be no whitespace at the end of the line.

Use common sense

To make code readable on the screen.

Line length

Must be kept to a maximum of 80 characters (or less). This allows reading of the code on laptops without side-scrolling.

Unix style line-breaks

Use unix style line-breaks rather windows line breaks.


Comments need to talk about the “why”. This is useful not just for others but for yourself when you read the code at a later time. They need to be well written and clear and need to state a date and an author if it is important commentary worth revisiting. For such revisit comments, a format has been specified below.

Revisit Comments

Use Revisit comments for code that is temporary, a short-term solution to be reworked, or for code on which there is still questions to be resolved or understood. Multiple related Revisit comments (that use same label) may be used across the project source, and across different languages.

A Revisit comments should have a:

  • !+ : must explicitly start with these 2 characters
  • label : for easier grepping, and to be able to relate multiple comments across the project source (even in different languages)
  • author identifier : so others know who to follow-up with if needed, this can be the github handle of the committer.
  • date : so it is easier to judge relevance and status at a later time
  • description : should also indicate what conditions/events would render the comment obsolete.

The following is an example of a revisit comment:

   * !+LINK_ROUTE(kohsah, 2017-12-31) Switching to using linkRoute instead of hard-coded link URL

Formal Documentation comments

These formal documentation comments allow running documentation generation tools to extract documentation from code. For this we recommend the following for different programming languages

  • Javascript - SphinxJS style comments for functions and modules
  • XQuery - XQDoc style comments for functions and modules
  • Java - JavaDoc style comments for functions and classes.

Language Specific Coding Guidelines

The below are coding guidelines of how the code is to be strucutured and written. The reason for doing this is to have consistent and readable code. Many programmging languages and frameworks provide multiple ways of doing the same thing - for e.g. in React JS you can declare components either declaring a class directly, or by calling a spefific createClass api, both approaches may look correct, but both result in different looking code – which reduces readability. These coding guidelines below for different languages and frameoworks encourage uniformity and consistency.

React JS

Our front-end is primarily using React JS, and we recommend following the Airbnb React JS coding style guide . Additionally we recommend the following guidelines for our React code-base.

ES 2015

We recommend using ES 2015 for all front-end code.


import { getLangs } from "../utils/i18nhelper";

is good,


is not good.

AJAX Http Client

Use axios (not fetch or XMLHttpRequest) for both client and server (Node) usage.

Reading/Writing Files

Use only async apis.

Callbacks vs Promises

Use Promises where possible. For APIs where there is no promise based version available, use an API promisifier (like bluebird)

Structuring Component includes

Provide a line of white space between different kinds of imports. for e.g. :

  //  external component includes
  import React from 'react';
  import axios from 'axios';

  //  utility function includes
  import {apiGetCall} from '../api';
  import {coerceIntoArray} from '../utils/generalhelper';

  // component & container includes
  import DivFeed from '../components/DivFeed';
  import DivListing from '../components/DivListing';
  import ExprAbstract from './ExprAbstract';
  import SearchListPaginator from '../components/SearchListPaginator';
  import GwSpinner from '../components/GwSpinner';

  // css & image includes
  import '../css/ListingContentColumn.css';