56 lines
1.7 KiB
JavaScript
56 lines
1.7 KiB
JavaScript
/**
|
|
* Loads a script from a specific URL. React Native cannot load a JS
|
|
* file/resource/URL via a <script> HTML element, so the implementation
|
|
* fetches the specified src as plain text (e.g. via XMLHttpRequest) and then
|
|
* evaluates the fetched string as JavaScript code (i.e. via the {@link eval}
|
|
* function).
|
|
*
|
|
* @param {string} url - The absolute URL from the which the script is to be
|
|
* (down)loaded.
|
|
* @returns {void}
|
|
*/
|
|
export function loadScript(url) {
|
|
let fetch;
|
|
const method = 'GET';
|
|
|
|
// Prefer the Fetch API. Apart from the fact that we're fetching the
|
|
// specified script as a static resource, the Fetch API provides more
|
|
// detailed errors.
|
|
if (typeof (fetch = window.fetch) === 'function') {
|
|
fetch = fetch(url, { method });
|
|
} else {
|
|
// Otherwise, fall back to the XMLHttpRequest API.
|
|
fetch
|
|
= new Promise(resolve => {
|
|
const xhr = new XMLHttpRequest();
|
|
|
|
xhr.responseType = 'text';
|
|
|
|
xhr.onreadystatechange = () => {
|
|
if (xhr.readyState === 4) {
|
|
resolve(xhr);
|
|
}
|
|
};
|
|
|
|
xhr.open(method, url, /* async */ true);
|
|
xhr.send();
|
|
});
|
|
}
|
|
|
|
return (
|
|
fetch
|
|
.then(response => {
|
|
switch (response.status) {
|
|
case 200:
|
|
return response.responseText || response.text();
|
|
|
|
default:
|
|
throw response.statusText;
|
|
}
|
|
|
|
})
|
|
.then(responseText => {
|
|
eval.call(window, responseText); // eslint-disable-line no-eval
|
|
}));
|
|
}
|