ttokutake / http-dataloader

Load data via HTTP globally

HttpDataLoader

HttpDataLoader is useful to load globally the immutable data like config file through HTTP.

Notice

• HttpDataLoader highly depends on DataLoader.
• Please prepare a JavaScript environment which allow to use ES6 Promise and Map classes, and fetch API.

Installation

npm install --save http-dataloader

Getting Started

Node.js (CommonJS)

const { default: HttpDataLoader } = require("http-dataloader");
HttpDataLoader.set({
  key: "some_config",
  url: "http://example.com/some_config.json"
});

async function some_function1() {
  const config = await HttpDataLoader.loadOne("some_config"); // Fetch the data from "url"
  // Use config as you like
  console.log(config);
}

async function some_function2() {
  const config = await HttpDataLoader.loadOne("some_config"); // Load the data on memory cache
  // Use config as you like
  console.log(config);
}

some_function1();
some_function2();

ES6 import/export

import HttpDataLoader from "http-dataloader";
HttpDataLoader.set({
  key: "some_config",
  url: "http://example.com/some_config.json"
});

function some_function1() {
  // Fetch the data from "url"
  HttpDataLoader.loadOne("some_config").then(config => {
    // Use config as you like
    console.log(config);
  });
}

function some_function2() {
  // Use the data on memory cache
  HttpDataLoader.loadOne("some_config").then(config => {
    // Use config as you like
    console.log(config);
  });
}

some_function1();
some_function2();

APIs

set(...{ key: string, url: string, requestInit?: object, responseType?: "text" | "json", transform?: string | object => any }): HttpDataLoader

Example

import HttpDataLoader from "http-dataloader";

HttpDataLoader.set(
  { key: "config1", url: "http://example.com/config1.json" },
  {
    key: "config2",
    url: "http://example.com/config2.json",
    responseType: "text"
  },
  {
    key: "config3",
    url: "http://example.com/config3.json",
    responseType: "text",
    transform: text => text.split(",")
  }
);

// You can use method chaining
HttpDataLoader.set({ key: "config1", url: "http://example.com/config1.json" })
  .set({
    key: "config2",
    url: "http://example.com/config2.json",
    responseType: "text"
  })
  .set({
    key: "config3",
    url: "http://example.com/config3.json",
    responseType: "text",
    transform: text => text.split(",")
  });

Parameters

• key: Key string to load the data by loadOne() and load().
• url: URL from which the data is loaded.
• requestInit: Request options same as Fetch API.
• responseType: "text" or "json".
• transform: Function to transform response body.

loadOne(key: string): any

Example

import HttpDataLoader from "http-dataloader"; // set() is done in other files

async function some_function() {
  const config2 = await HttpDataLoader.loadOne("config2");
  // Use config2 as you like
}

load(...keys: string[]): any[]

Example

import HttpDataLoader from "http-dataloader"; // set() is done in other files

async function some_function() {
  const [config1, config2, config3] = await HttpDataLoader.load(
    "config1",
    "config2",
    "config3"
  );
  // Use config1, config2 and config3 as you like
}

clear(...keys: string[]): HttpDataLoader

Example

import HttpDataLoader from "http-dataloader"; // set() is done in other files

async function some_function1() {
  HttpDataLoader.clear("config2", "config3");
  const [config2, config3] = await HttpDataLoader.load("config2", "config3");
  // Use fresh config2 and config3 as you like
}

// You can use method chaining
async function some_function2() {
  const config2 = await HttpDataLoader.clear("config2").loadOne("config2");
  // Use fresh config2 as you like
}

clearAll(): HttpDataLoader

Example

import HttpDataLoader from "http-dataloader"; // set() is done in other files

async function some_function1() {
  HttpDataLoader.clearAll();
  const [config1, config2, config3] = await HttpDataLoader.load(
    "config1",
    "config2",
    "config3"
  );
  // Use fresh config1, config2 and config3 as you like
}

// You can use method chaining
async function some_function2() {
  const [config1, config2, config3] = await HttpDataLoader.clearAll().loadOne(
    "config1",
    "config2",
    "config3"
  );
  // Use fresh config1, config2 and config3 as you like
}