old_contents: /* jshint node: true */
  'use strict';
  
  let fs = require('fs');
  
  module.exports = {
    name: 'ember-cli-ifa',
  
    isDevelopingAddon: function() {
      return false;
    },
  
    included: function(app) {
      this.app = app;
      this._super.included.apply(this, arguments);
    },
  
    postBuild: function (build) {
      let fingerprintPrepend = '/';
      let indexFilePath = build.directory + '/index.html';
      let indexFileBuffer = fs.readFileSync(indexFilePath);
      let indexFile = indexFileBuffer.toString('utf8');
  
      let files = fs.readdirSync(build.directory + '/assets');
      let totalFiles = files.length;
  
      let assetFileName = null;
      for (let i = 0; i < totalFiles; i++) {
        if (files[i].match(/^assetMap/i)) {
          assetFileName = files[i];
          break;
        }
      }
  
      // Prepend the URL of the assetMap with the location defined in fingerprint
      // options.
      if (this.app && this.app.options && this.app.options.fingerprint) {
        fingerprintPrepend = this.app.options.fingerprint.prepend;
      }
  
      let assetMapContent = 'false';
      if (assetFileName) {
        assetMapContent = `"${fingerprintPrepend + 'assets/' + assetFileName}"`;
      }
      fs.writeFileSync(
        indexFilePath,
        indexFile.replace(/__asset_map_placeholder__/, assetMapContent)
      );
    },
  
    contentFor(type, config) {
      if (type === 'head-footer' && config.ifa && config.ifa.enabled) {
        return '<script>var __assetMapFilename__ = __asset_map_placeholder__;</script>';
      }
    }
  };
  
new_contents: /* jshint node: true */
  'use strict';
  
  let fs = require('fs');
  
  module.exports = {
    name: 'ember-cli-ifa',
  
    isDevelopingAddon: function() {
      return false;
    },
  
    included: function(app) {
      this.app = app;
      this._super.included.apply(this, arguments);
    },
  
    postBuild: function (build) {
      let fingerprintPrepend = '/';
      let indexFilePath = build.directory + '/index.html';
      let indexFileBuffer = fs.readFileSync(indexFilePath);
      let indexFile = indexFileBuffer.toString('utf8');
  
      let files = fs.readdirSync(build.directory + '/assets');
      let totalFiles = files.length;
  
      let assetFileName = null;
      for (let i = 0; i < totalFiles; i++) {
        if (files[i].match(/^assetMap/i)) {
          assetFileName = files[i];
          break;
        }
      }
  
      // Prepend the URL of the assetMap with the location defined in fingerprint
      // options.
      if (this.app && this.app.options && this.app.options.fingerprint) {
        fingerprintPrepend = this.app.options.fingerprint.prepend;
      }
  
      let assetMapContent = null;
      if (assetFileName) {
        assetMapContent = `"${fingerprintPrepend + 'assets/' + assetFileName}"`;
      }
      fs.writeFileSync(
        indexFilePath,
        indexFile.replace(/__asset_map_placeholder__/, assetMapContent)
      );
    },
  
    contentFor(type, config) {
      if (type === 'head-footer' && config.ifa && config.ifa.enabled) {
        return '<script>var __assetMapFilename__ = __asset_map_placeholder__;</script>';
      }
    }
  };
  
subject: replace 'false' with null