chai/lib/chai/utils/objDisplay.js

BDD/TDD assertion library for node.js and the browser. Test framework agnostic.

/*!
 * Chai - flag utility
 * Copyright(c) 2012-2014 Jake Luer <jake@alogicalparadox.com>
 * MIT Licensed
 */

import {inspect} from './inspect.js';
import {config} from '../config.js';

/**
 * ### .objDisplay(object)
 *
 * Determines if an object or an array matches
 * criteria to be inspected in-line for error
 * messages or should be truncated.
 *
 * @param {unknown} obj javascript object to inspect
 * @returns {string} stringified object
 * @name objDisplay
 * @namespace Utils
 * @public
 */
export function objDisplay(obj) {
  let str = inspect(obj),
    type = Object.prototype.toString.call(obj);

  if (config.truncateThreshold && str.length >= config.truncateThreshold) {
    if (type === '[object Function]') {
      return !obj.name || obj.name === ''
        ? '[Function]'
        : '[Function: ' + obj.name + ']';
    } else if (type === '[object Array]') {
      return '[ Array(' + obj.length + ') ]';
    } else if (type === '[object Object]') {
      let keys = Object.keys(obj),
        kstr =
          keys.length > 2
            ? keys.splice(0, 2).join(', ') + ', ...'
            : keys.join(', ');
      return '{ Object (' + kstr + ') }';
    } else {
      return str;
    }
  } else {
    return str;
  }
}