gulp-function/ts/index.ts

88 lines
2.3 KiB
TypeScript

import * as smartpromise from '@pushrocks/smartpromise';
import * as through2 from 'through2';
import { Transform } from 'stream';
export type TExecutionMode = 'forEach' | 'forFirst' | 'atEnd';
export interface IPromiseFunction {
(file?, enc?): PromiseLike<any>;
}
let defaultExport = (
functionsToExecuteArg: IPromiseFunction | IPromiseFunction[],
executionModeArg: TExecutionMode = 'forEach'
): Transform => {
let promiseArray = [];
let runFunction = function(functionArg, file, enc) {
let returnValue = functionArg(file, enc);
if (typeof returnValue !== 'undefined' && typeof returnValue.then !== 'undefined') {
promiseArray.push(returnValue);
}
};
let checkAndRunFunction = function(file, enc) {
if (typeof functionsToExecuteArg === 'function') {
runFunction(functionsToExecuteArg, file, enc);
} else if (Array.isArray(functionsToExecuteArg)) {
for (let anyFunction in functionsToExecuteArg) {
runFunction(functionsToExecuteArg[anyFunction], file, enc);
}
} else {
throw new Error('gulp-callfunction: something is strange with the given arguments');
}
return Promise.all(promiseArray);
};
let hasExecutedOnce = false;
let forEach = function(file, enc, cb) {
// the forEach function is called for every chunk
switch (executionModeArg) {
case 'forEach':
checkAndRunFunction(file, enc).then(function() {
cb(null, file);
});
break;
case 'forFirst':
if (hasExecutedOnce) {
checkAndRunFunction(file, enc).then(function() {
cb(null, file);
});
} else {
cb(null, file);
}
hasExecutedOnce = true;
break;
case 'atEnd':
cb();
break;
default:
break;
}
};
let atEnd = function(cb) {
if (executionModeArg === 'atEnd') {
checkAndRunFunction(null, null).then(function() {
cb();
});
} else {
cb();
}
};
return through2.obj(forEach, atEnd);
};
export let forEach = (funcArg: IPromiseFunction) => {
return defaultExport(funcArg, 'forEach');
};
export let forFirst = (funcArg: IPromiseFunction) => {
return defaultExport(funcArg, 'forFirst');
};
export let atEnd = (funcArg: IPromiseFunction) => {
return defaultExport(funcArg, 'atEnd');
};
export default defaultExport;