A custom Jasmine matcher to check a component for a particular string

to_have_text_matcher.js

var $ = require('jquery');
var resolveDOMNode = require('support/resolve_dom_node');

/**
 * This file adds a `toHaveText` matcher to our Jasmine spec. To use it, do
 * something like:
 *
 *   expect(component).toHaveText('Support John');
 */
beforeEach(function() {
  jasmine.addMatchers({
    toHaveText: function() {
      return {
        /**
         * @param {Object} node A rendered React component, or a DOM node
         * @param {string} expectedText The text you expect this node/component
         *   to have
         * @param {Object} options
         * @param {boolean} options.exact if true, performs an exact match
         * @param {boolean} options.caseInsensitive if true, performs a
         *   case-insensite match.
         * @return {Object}
         */
        compare: function(node, expectedText, options = {}) {
          var result     = {},
              domNode    = resolveDOMNode(node),
              actualText = $(domNode).text(),
              contain    = 'contain';

          if (options.caseInsensitive) {
            actualText   = actualText.toLowerCase();
            expectedText = expectedText.toLowerCase();
          }

          if (options.exact) {
            result.pass = actualText === expectedText;
            contain     = 'be';
          } else {
            result.pass = actualText.indexOf(expectedText) !== -1;
          }

          if (result.pass) {
            result.message = `Expected "${actualText}" not to ${contain} "${expectedText}"`;
          } else {
            result.message = `Expected "${actualText}" to ${contain} "${expectedText}"`;
          }

          return result;
        }
      };
    }
  });
});