Alize.js

HTTP Client in JavaScript using Fetch API

Why Alize.js?

1. to avoid hard-coding urls when doing ajax.
2. to assert the structure of the request parameter object.
3. to assert the structure of the response JSON.

Installation

npm i --save alize

Requirements

• whatwg-fetch
  • to use Fetch API in browser environment (you can use another polyfill)

Examples

const alize = require('alize');

const alizeBuilder = alize.setup({
  urls: [
    {
      url: '/foo',
      method: 'get',
    },
    {
      url: '/foo/:id',
      method: 'post',
      assert: {
        pre: {
          {
            x: {
              require: true,
            },
          },
        },
        post: {
          {
            message: {
              require: true,
            },
          },
        },
      },
    },
    {
      url: '/bar',
      template: 'resources',
      only: ['show', 'new', 'destroy'],
    },
  ],
  option: {
    logMode: 'error',
    headers: {
      'Content-Type': 'application/json',
    },
  },
});

const client = alizeBuilder.getClient();

client.foo.get(); // GET /foo
client.foo.post({ urlParam: { id: 1 }, data: { x: 'x' } }); // POST /foo/:id
client.bar.destroy({ urlParam: { id: 1 } }); // DELETE /bar/:id

This example generate a object (Alize object), which has methods to fetch remote data, and validate the parameter object and the returned JSON.

You can also add such a method after initializing.

const alizeBuilder = alize.setup();

// You can now access .foo.get
alizeBuilder.add({ url: '/foo', method: 'get' });

const client = alizeBuilder.getClient();
client.foo.get(); // GET /foo

Configuration

Alize's setup method receives an object which has properties below.

|name|type|description| |urls|Array(object)|Used to initialize UrlConfig object| |template|object|Used to generate template functions| |option|object|Set common options. You can set such values as the log level, headers, and so on|

UrlConfig

Alize generates methods as specified in a UrlConfig object. You can initialize a UrlConfig object through alize.setup method or Alize.add method.

For example,

const param = {
  urls: [
    { url: '/foo', method: 'get' }, // This is used to initialize UrlConfig object.
  ],
};
const alizeBuilder = alize.setup(param);

// alize.setup returns Alize object. You can call add method to generate another method.
alizeBuilder.add({ url: '/foo:id', method: 'delete' });

The UrlConfig constructor receives such a object as specified below.

Property

name	type	description	required
url	string	Url path. If the url has dynamic values, then use colon. e.g. /foo/:id/bar	true
method	string	The same parameter as the fetch API's method. e.g. get, post, delete, put...	or template
template	string	Template method. You can generate multiple methods with this	or method
only	Array(string)	When you use template, alize generates methods which is only specified here	false
path	string	access path to the generated method	false
headers	object	The same parameter as the fetch API's headers. e.g. { 'Content-Type': 'application/json' }	false
credentials	string	The same parameter as the fetch API's credentials. e.g. 'same-origin'	false
assert	object	Used to validate post parameters and the returned JSON	false
process	object	Used to process parameter object before fetching or the returned JSON after fetching	false
logMode	string	Specify log level. the default value is 'silent' e.g. 'error', 'warn', 'info', 'log', 'debug'	false

Path

The access path to the method is determined as below.

1. If the path is specified, then the value is that.

• e.g. 'foo.bar'

1. If the path is /, then the access path will be 'root'
2. Thrashes in the path is replaced by dots, and the dynamic parameters and superfluous dots are removed

• e.g. '/foo/:id/bar' -> 'foo.bar'

const alizeBuilder = alize.setup();
alizeBuilder
  .add({ url: 'foo', method: 'get' })
  .add({ url: 'foo/:id/bar', template: 'resources', only: ['index'] });

const client = alizeBuilder.getClient();
client.foo.get(); // When the method is specified, method name will be the value
clinet.foo.bar.index(); // When the template is specified, methods' name will be the template methods' name

Template

Alize has two default template methods.

resources

Generates methods below. This crresponds to the Rails' resources.

method	WebAPI	url
index	GET	{path}
show	GET	{path}/:id
create	POST	{path}
edit	GET	{path}/:id/edit
update	PUT	{path}/:id
destroy	DELETE	{path}/:id

rest

Generates methods below.

method	WebAPI	url
get	GET	{path}
put	PUT	{path}
post	PUT	{path}
patch	PUT	{path}
delete	PUT	{path}

Example

const alizeBuilder = alize.setup({
  urls: [{ url: 'foo', template: 'resources' }],
});

const client = alizeBuilder.getClient();
client.foo.index(); // GET /foo

// You can call a template method directly.
alizeBuilder.resources('/bar');
client.bar.show({ urlParam: { id: 1 } }); // GET /bar/1

You can also add your original template methods.

const alizeBuilder = alize.setup({
  template: {
    original: function (baseUrl) { // receives url path string
      'methodName': {
        url: `${baseUrl}/:id`,
        method: 'get',
      },
    },
  },
});

// Now you can use 'original' template.
alizeBuilder.original('/foo');

const client = alizeBuilder.getClient();
client.foo.methodName({ urlParam: { id: 1 } }); // GET /foo/1

Assert

You can validate the parameters before fetching, and also the returned JSON (when content-type is 'application/json') after fetching.

Assert Property

name	type	description
pre	object	Used to validate the parameters before fetching
post	object	Used to validate the returned JSON

pre and post's object has such a structure as

const pre = {
  [property]: {
    type: [type value], // this is the returned value of typeof operator.
    checks: {
      'enum': { // Specified when the value is limited.
        array: [array of values],
      },
      'require': { // If always required, then you can also set true.
        when: {
          present: [Array of property names],
          // When some of the specified properties are present in the object, then the object must have the property.
          absent: [Array of property names]
          // When some the specified properties are not present in the object, then the object must have the property.
        },
      },
      'forbid': {
        when: {
          present: [Array of property names],
          // When some of the specified properties are present in the object, then the object mustn't have the property.
          absent: [Array of property names]
          // When some the specified properties are not present in the object, then the object mustn't have the property.
        },
      },
    },
  },
};

Examples

const assert = {
  pre: {
    x: {
      type: 'string',  // x's type is string,
      checks: {
        require: true, // and post parameter must include 'x'.
      },
    },
    y: {
      type: 'number',
      checkes: {
        require: {
          when: {
            absent: ['z'], // y is required when the parameter doesn't have the property 'z',
          },
        },
        forbid: {
          when: {
            present: ['z'], // and y is forbidden when the parameter has the property 'z'.
          },
        },
      },
    },
  },
};

const alizeBuilder = alize.setup({
  urls: [{ url: '/foo', method: 'get', option: { assert } }],
});

Process

You can convert parameters or returned JSON before or after fetching.

Property

name	type	description
pre	function	Used to process the parameters before fetching
post	function	Used to process the returned JSON

Examples

const process = {
  pre(param) {
    return param;
  },
  post(json) {
    return json;
  },
};

const alizeBuilder = alize.setup({
  urls: [{ url: '/foo', method: 'get', option: { process } }],
});

API

setup (object) => Alize

Please refer to the configuration details.

build (object) => AlizeClient

const alizeBuilder = alize.setup();
let alizeClient = alizeBuilder.getClient();

// This is the same as above.
alizeClient = alize.build();

Alize

getClient (void) => AlizeClient

const alizeBuilder = alize.setup();
const alizeClient = alizeBuilder.getClient();

add (object) => Alize(this)

const alizeBuilder = alize.setup();
alizeBuilder.add({ url: '/foo', method: 'get' })
  .add({ url: 'bar', method: 'post' });

template method (string, object) => Alize(this)

receives url path string and fetch option object, then generate methods to fetch.

const alizeBuilder = alize.setup();
alizeBuilder
  .resources('bar')
  .get('foo', {
    headers: {
      'Content-Type': 'text/html'
    },
    credentials: 'same-origin',
    process: {
      post(json) {
        return json.message;
      },
    },
  });

const alizeClient = alizeBuilder.getClient();
alizeClient.bar.show({ urlParam: { id : 1 }); // GET /bar/:id
alizeClient.foo.get(); // GET /foo

The default template methods are below. Please also refer to the template details

• resources
• rest
• get
• post
• delete
• put
• patch
• head
• options

AlizeClient

AlizeClient has the generated metods.

Generated method

receives post parameter and fetch remote data.

Parameter Property

name	type	description
urlParam	object	When the url has parameters, then the value is specified here
data	object	The same parameter as the fetch API's data

const client = alize.build({ urls: [{ url: 'foo/:id', method: 'get' }] });
client.foo.get({ urlParam: { id: 1 }, data: { x: 2 } }); // GET /foo/1?x=2

You can't set other fetch options here. If you'd like to set options dynamically, then use the next Fetch API wrapper method.

Fetch API wrapper

AlizeClient has the methods which wrap fetch API, other than the generated methods. You can fetch data with calling such methods as get, post, and so on.

const client = alize.setup().getClient();

// GET /foo?id=1
client.get('/foo', { id: 1 }, { 'Content-Type': 'application/json' });