jrf-pip
v1.0.0
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parallel iteration processing
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jrf-pip (parallel iteration processing)
jrf-pip - This is a package for parallel iterative processing of large arrays. Allows parallel processing asynchronously, or asynchronously in synchronous style. Processing implemented through Promise.all()
Example
const parallelProcessing = require('jrf-pip');
// Send a message to group users
async function sendMesToGroupUsers() {
// Generate groups of 10,000 users.
// 5000 female
// 5000 males
const groupUsers = generateUsers();
// Filter Function
// Skip Male Users
// i.e. send message only to female
const nextValueFn = ({value, index, arrayValues, iteration}) => {
return value.sex === 'male';
};
// Processing Function
// Send a message
const processingFn = ({value, index, arrayValues, iteration}) => {
const user = value;
user.sendMes(iteration);
};
// Callback function. It will work after the completion of sending the message.
const cb = (stackError) => console.log('Finish parallel iteration processing');
// Starting parallel iterative processing
// An array of arrayValues is specified for processing
// filter function nextValueFn specified
// the processing function of the processingFn array element is specified
// a callback function is set that will be executed when parallel processing is completed
// set the number of 1000 parallel processed array values through Promise.all()
await parallelProcessing({
arrayValues: groupUsers,
nextValueFn,
processingFn,
cb,
parallel: 1000
});
console.log('Before finish');
}
// Send a message to the users of the group in a synchronous style
async function sendMesToGroupUsersSyncStyle() {
// Generate groups of 10,000 users.
// 5000 female
// 5000 males
const groupUsers = generateUsers();
// Filter Function
// Skip Male Users
// i.e. send message only to female
const nextValueFn = ({value, index, arrayValues, iteration}) => {
return value.sex === 'male';
};
// Processing Function
// Send a message
const processingFn = ({value, index, arrayValues, iteration}) => {
const user = value;
user.sendMes(iteration);
};
// Starting parallel iterative processing
// An array of arrayValues is specified for processing
// filter function nextValueFn specified
// the processing function of the processingFn array element is specified
// the awaitRes response wait parameter is specified i.e. synchronous execution
// set the number of 2000 parallel values of the array through Promise.all()
// time of cycleTimeout of an asynchronous pause between iterations is set
const stackError = await parallelProcessing({
arrayValues: groupUsers,
nextValueFn,
processingFn,
awaitRes: true,
parallel: 2000,
cycleTimeout: 100
});
console.log('Finish parallel iteration processing in sync style');
}
function generateUsers(count = 10000) {
const groupUsers = [];
const even = n => !(n % 2);
for (let i = 1; i <= count; i++) {
const sex = even(i) ? 'male' : 'female';
groupUsers.push({
id: i,
sex,
sendMes(iteration) {
console.log(`send mes to user id: ${this.id} sex: ${this.sex} iteration: ${iteration}`);
}
});
}
return groupUsers;
}
Promise.resolve()
.then(sendMesToGroupUsers)
.then(sendMesToGroupUsersSyncStyle)
.catch(e => console.error(e));
Parameters
The parallelProcessing function at the input accepts the following parameters:
| name | type | required | default | description |
| --- | --- | --- | --- | --- |
| arrayValues | array | true | | An array of values to process |
| processingFn | function | true | | A synchronous or asynchronous function that processes an array element. The input accepts parameters paramsForFunction |
| nextValueFn | function | false | | A synchronous or asynchronous function that performs filtering. If it returns true, then the current element of the array will not be processed. false - the current element of the array will be processed. The input accepts parameters paramsForFunction |
| parallel | number | false | 1000 | Number of elements to be processed in parallel per iteration |
| awaitRes | boolean | false | false | Expect an answer i.e. wait for completion to complete in synchronous style |
| cb | function | false | | A synchronous or asynchronous callback function, will work if awaitRes = false
. An error stack will be passed to the function stackError |
| cycleTimeout | number | false | 200 | Asynchronous pause between iterations (milliseconds), for awaitRes = true
|
paramsForFunction
Parameters passed to the processingFn and nextValueFn function
| name | type | description | | --- | --- | --- | | value | any | Array element to process | | index | number | Array element index | | arrayValues | array | Array | | iteration | number | Iteration number |
stackError
An error stack returned with awaitRes = true
, or passed to a function
callback when awaitRes = false
.
Array of objects:
| name | type | description | | --- | --- | --- | | value | any | Array element during processing of which an error occurred | | index | number | Array element index | | iteration | number | Iteration number | | error | object | Error |