simple-jsonp-promise/index.js
2017-08-07 20:24:25 +08:00

65 lines
2 KiB
JavaScript

/**
* Created by lizq on 2017/8/7
*/
// Callback index.
let count = 0;
/**
* JSONP handler
*
* Options:
* - prefix {String} callback prefix (defaults to `__jp`)
* - jsonp {String} qs jsonpeter (defaults to `callback`)
* - timeout {Number} how long after the request until a timeout error
* is emitted (defaults to `15000`)
*/
let jsonp = function( url, options ) {
options = options || {};
let prefix = options.prefix || '__jp';
let jsonp = options.jsonp || 'callback';
let params = options.params || {};
let timeout = options.timeout ? options.timeout : 15000;
let target = document.getElementsByTagName( 'script' )[ 0 ] || document.head;
let script;
let timer;
let cleanup;
let promise;
let noop = function() {};
// Generate a unique id for the request.
let id = prefix + (count++);
cleanup = function() {
// Remove the script tag.
if ( script && script.parentNode ) {
script.parentNode.removeChild( script );
}
window[ id ] = noop;
if ( timer ) { clearTimeout( timer ); }
};
promise = new Promise( ( resolve, reject ) => {
if ( timeout ) {
timer = setTimeout( function() {
cleanup();
reject( new Error( 'Timeout' ) );
}, timeout );
}
window[ id ] = function( data ) {
cleanup();
resolve( data );
};
params[ jsonp ] = id;
for ( let key in params ) {
url += (~url.indexOf( '?' ) ? '&' : '?') + key + '=' + encodeURIComponent( params[ key ] );
}
url = url.replace( '?&', '?' );
// Create script.
script = document.createElement( 'script' );
script.src = url;
script.onerror = function() {
cleanup();
reject( new Error( 'Network Error' ) );
};
target.parentNode.insertBefore( script, target );
} );
return promise;
};
export default jsonp;