npm install ajax-caching!Travis

!npm downloads

* It could help you quickly AJAX caching result.
``sh`
npm install ajax-caching
* use cache
`js`
const compilerURL = 'https://solc-bin.ethereum.org/bin/soljson-v0.4.25+commit.59dbf8f1.js';
const opts = { url: compilerURL, caching: true };
let source = await promiseAjax(opts);
* don't use cache
`js`
const compilerURL = 'https://solc-bin.ethereum.org/bin/soljson-v0.4.25+commit.59dbf8f1.js';
const opts = { url: compilerURL, caching: false };
let source = await promiseAjax(opts);
* simple to use
`js``
const compilerURL = 'https://solc-bin.ethereum.org/bin/soljson-v0.4.25+commit.59dbf8f1.js';
let source = await promiseAjax(compilerURL);