App Integration with FAST


Integrating FAST technology into other JavaScript projects can be done with the @f5devcentral/f5-fast-core NPM module.

The @f5devcentral/f5-fast-core module:

  • Parses Mustache templates and an extended template format (in YAML)
  • Supports Mustache partials and sections
  • Generates a view schema from parsed template data
  • Renders templates with user-provided views
  • Validates user-provided views against generated view schema
  • Includes a command line interface


The @f5devcentral/f5-fast-core module can be installed from NPM via:

npm install @f5devcentral/f5-fast-core

Example Usage

Below is a basic example for loading a template without any additional type schema:

const fast = require('@f5devcentral/f5-fast-core');

const ymldata = `
      message: Hello!
    template: |
        {{> body}}

    .then((template) => {
        console.log(template.render({message: "Hello world!"}));

In addition to Template.loadYaml(), a Template can be created from Mustache data using Template.loadMst():

const fast = require('@f5devcentral/f5-fast-core');

const mstdata = '{{message}}';

    .then((template) => {
        console.log(template.render({message: "Hello world!"}));

To support user-defined types, a SchemaProvider must be used.

The FsSchemaProvider can be used to load schema from disk:

const fast = require('@f5devcentral/f5-fast-core');

const templatesPath = '/path/to/templatesdir'; // directory containing types.json
const schemaProvider = new fast.FsSchemaProvider(templatesPath);
const mstdata = '{{virtual_port:types:port}}';

fast.Template.loadMst(mstdata, schemaProvider)
    .then((template) => {
        console.log(template.render({virtual_port: 443});

A higher-level API is available for loading templates via TemplateProvider classes. These classes will handle calling the correct load function (Template.loadYaml() vs Template.loadMst()) and can also handle schemas.

For example, to load “templates sets” (a collection of template source files) from a given directory, the FsTemplateProvider class can be used:

const fast = require('@f5devcentral/f5-fast-core');

const templatesPath = '/path/to/templatesdir';
const templateProvider = fast.FsTemplateProvider(templatesPath);

    .then((template) => {
            var: "value",
            boolVar: false


A command line interface is provided via a fast binary. The help text is provided below and also accessed via fast --help:

fast <command>

  fast validate <file>                                validate given template source file
  fast schema <file>                                  get template parameter schema for given template source file
  fast validateParameters <tmplFile> <parameterFile>  validate supplied template parameters with given template
  fast render <tmplFile> [parameterFile]              render given template file with supplied parameters
  fast validateTemplateSet <templateSetPath>          validate supplied template set
  fast htmlpreview <tmplFile> [parameterFile]         generate a static HTML file with a preview editor to standard out
  fast packageTemplateSet <templateSetPath> [dst]     build a package for a given template set

  --help     Show help                                                                                         [boolean]
  --version  Show version number                                                                               [boolean]

For more information on a given command use the --help flag combined with a command:

fast <command> --help

The CLI can also be accessed by executing cli.js. For example:

./cli.js render path/to/template