promises-runner
v0.0.21
Published
Run promises in batches waiting for data from previous promises, pause/resume/stop promises.
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promises-runner
Run promises from an array of objects waiting for some promises to be resolved before continuing running others
Install
npm install --save promises-runner
Api
PromisesRunner({
objectsArrayWithPromises: [Object], // default []
inputData: Object, // default {}
outputDataKey: string|false, // default false
mergePromiseOutputToNextPromiseInput: true|false, // default false
mergeSameKeyByConvertingToArray: true|false, // default false
logger: Function|false // default false
})
objectsArrayWithPromises single object should be
{promise: (inputData) => Promise, wait: true|false, outputKey: string}
logger function
logger: (action: String, objectFromArrayWithPromises: Object, inputOutputOrError: Mixed)
action
= START|ERROR|DONE
objectFromArrayWithPromises
= one object from objectsArrayWithPromises
with (promiseName
)
inputOutputOrError
= would be input of promise if action = START,
output of promise if action = DONE
and error if action = ERROR
Check example logger function at end of README
Usage example
var PromisesRunner = require('promises-runner')
function expensiveOperation(value) {
return Promise.resolve(value)
}
const objectsArrayWithPromises = [
{promise: expensiveOperation}, // <--┐
{promise: expensiveOperation}, // <----- these will run in parallel
{promise: expensiveOperation}, // <--┘
{promise: expensiveOperation, wait: true}, // this will wait before all previous are resolved
{promise: expensiveOperation}, // these 2 -- after the previous one is resolved
{promise: expensiveOperation}, // these 2 -- and are ran in parallel
{promise: expensiveOperation, wait: true}, // this will wait before all previous are resolved
{promise: expensiveOperation}, // these 2 -- after the previous one is resolved
{promise: expensiveOperation}, // these 2 -- and are ran in parallel
]
var pr = new PromisesRunner({objectsArrayWithPromises});
pr.start();
// pause/resume PromisesRunner
const resume = pr.pause();
resume();
// stop promises runner,
// this will send currentOutput and
// promise.then will be called after completion of promises already running (parallel ones)
const currentOutput = pr.stop();
Example of objects being merged as per outputKey and mergePromiseOutputToNextPromiseInput
const sleepFor = (seconds, value, valueAs, d) => new Promise(resolve => (
setTimeout(() => resolve(value ? {[valueAs]: value} : {}), seconds)
));
const allPromises = [
{promise: (d) => sleepFor(1, 'action1', 'a1', d)},
{promise: (d) => sleepFor(3, 'action2', 'a2', d)},
{promise: (d) => sleepFor(1, 'action3w', 'a3', d), wait: true},
{promise: (d) => sleepFor(8, 'action4', 'a4', d)},
{promise: (d) => sleepFor(1, 'action5', 'a5', d)},
{promise: (d) => sleepFor(2, 'action6w', 'a6', d), wait: true},
{promise: (d) => sleepFor(2, 'action7', 'a7', d)},
{promise: (d) => sleepFor(5, 'action8w', 'a8', d), wait: true},
{promise: (d) => sleepFor(2, 'action9', 'a9', d)},
{promise: (d) => sleepFor(1, 'action10', 'a10', d), outputKey: 'abc'},
];
new PromisesRunner({
objectsArrayWithPromises: allPromises,
inputData: {someInputData: -1},
outputDataKey: 'outputKey', // default false
mergePromiseOutputToNextPromiseInput: true // default false
})
.start()
.then(console.log)
/*
for outputDataKey = 'outputKey', mergePromiseOutputToNextPromiseInput = true
input for all promises: {someInputData: -1, outputKey: {a1: 'action1', a2: 'action2' ....}}
output:
{
outputKey: {
a1: 'action1',
a2: 'action2',
a3: 'action3w',
a4: 'action4',
a5: 'action5',
a6: 'action6w',
a7: 'action7',
a8: 'action8w',
a9: 'action9',
abc: {
a10: 'action10'
}
}
}
*/
/*
for outputDataKey = false, mergePromiseOutputToNextPromiseInput = true
input for all promises: {someInputData: -1, a1: 'action1', a2: 'action2' ....}
output:
{
a1: 'action1',
a2: 'action2',
a3: 'action3w',
a4: 'action4',
a5: 'action5',
a6: 'action6w',
a7: 'action7',
a8: 'action8w',
a9: 'action9',
abc: {
a10: 'action10'
}
}
*/
/*
for default outputDataKey = false, mergePromiseOutputToNextPromiseInput = false
input for all promises: {someInputData: -1}
output:
{
a1: 'action1',
a2: 'action2',
a3: 'action3w',
a4: 'action4',
a5: 'action5',
a6: 'action6w',
a7: 'action7',
a8: 'action8w',
a9: 'action9',
abc: {
a10: 'action10'
}
}
*/
Example logger
taskLogger.js
const chalk = require('chalk');
const lowerCase = require('lodash/lowerCase');
const pad = require('lodash/pad');
module.exports = (action, relatedPromiseRunnerObject, relatedData) => {
let consoleColor = chalk;
switch (action) {
case 'START':
consoleColor = chalk.bgKeyword('orange');
break;
case 'DONE':
consoleColor = chalk.bgKeyword('green');
break;
case 'ERROR':
consoleColor = chalk.bgKeyword('red');
break;
}
console.log(consoleColor(`[${pad(action, 9)}]`), '==>', lowerCase(relatedPromiseRunnerObject.promiseName));
};