How to use the bpk-tokens/tokens/base.raw.json.props function in bpk-tokens

import svg2react from './tasks/svg2react';
import svg2datauri, { sassMap, svg2sassvar } from './tasks/svg2datauri';
import getIconFontMetadataProvider from './tasks/getIconFontMetadataProvider';
import metadata from './tasks/metadata';

const remToPx = value => {
  let parsed = null;

  if (/rem$/.test(value)) {
    parsed = parseFloat(value.replace(/rem/, '')) * 16;
  }

  return parsed || null;
};

const smallIconSize = tokens.props.ICON_SIZE_SM.value;
const smallIconPxSize = remToPx(smallIconSize);
const largeIconSize = tokens.props.ICON_SIZE_LG.value;
const largeIconPxSize = remToPx(largeIconSize);

const colors = _(tokens.props)
  .filter({ category: 'colors', type: 'color' })
  .keyBy('name')
  .mapValues('value')
  .mapKeys((value, key) => _.kebabCase(key).replace('color-', ''))
  .mapValues(value => tinycolor(value).toHexString())
  .value();

const svgoCommonPlugins = [
  { removeTitle: true },
  { removeStyleElement: true },
  { removeEmptyContainers: true },

import getIconFontMetadataProvider from './tasks/getIconFontMetadataProvider';
import metadata from './tasks/metadata';

const remToPx = value => {
  let parsed = null;

  if (/rem$/.test(value)) {
    parsed = parseFloat(value.replace(/rem/, '')) * 16;
  }

  return parsed || null;
};

const smallIconSize = tokens.props.ICON_SIZE_SM.value;
const smallIconPxSize = remToPx(smallIconSize);
const largeIconSize = tokens.props.ICON_SIZE_LG.value;
const largeIconPxSize = remToPx(largeIconSize);

const colors = _(tokens.props)
  .filter({ category: 'colors', type: 'color' })
  .keyBy('name')
  .mapValues('value')
  .mapKeys((value, key) => _.kebabCase(key).replace('color-', ''))
  .mapValues(value => tinycolor(value).toHexString())
  .value();

const svgoCommonPlugins = [
  { removeTitle: true },
  { removeStyleElement: true },
  { removeEmptyContainers: true },
  { sortAttrs: true },
  { removeUselessDefs: true },

const _ = require('lodash');
const tinycolor = require('tinycolor2');
const tokens = require('bpk-tokens/tokens/base.raw.json');

const colors = _(tokens.props)
  .filter({ category: 'colors', type: 'color' })
  .keyBy('name')
  .mapValues('value')
  .mapKeys((value, key) => _.kebabCase(key).replace('color-', ''))
  .mapValues(value => tinycolor(value).toHexString())
  .value();

module.exports = function gruntConfig(grunt) {
  grunt.loadNpmTasks('grunt-contrib-clean');
  grunt.loadNpmTasks('grunt-contrib-copy');
  grunt.loadNpmTasks('grunt-svgmin');
  grunt.loadNpmTasks('grunt-exec');
  grunt.loadTasks('tasks');

  grunt.initConfig({