I have a usercase where I get an array of functions from backend something like:
var arr = [A(){}, B(){}, C(){}];
Now I need a way to execute them such that each function in the array is passed as a parameter to another function in the array.
A(B(C()));
I'm curious how you managed to get the functions from the back-end, but it doesn't matter for your question, so here goes your answer:
var arr = [A(){}, B(){}, C(){}];
var value = arr[arr.length - 1]();
for (var i = arr.length - 2; i >= 0; i--) {
value = arr[i](value);
}
console.log(value);
You can use Array.prototype.reduce to execute consecutive calls to a list of functions.
Update: As ASDFGerte suggests, you can use reduceRight instead of reduce to reverse the function execution flow.
const text = 'That will be 3.50';
const funcList = [extractNumber, parseNumeric, formatCurrency];
console.log('Parsed:', chainFunctions(funcList, text));
console.log('Parsed:', chainFunctionsReverse(funcList.reverse(), text));
function chainFunctions(funcList, startingValue) {
return funcList.reduce((result, func) => func(result), startingValue);
}
function chainFunctionsReverse(funcList, startingValue) {
return funcList.reduceRight((result, func) => func(result), startingValue);
}
function extractNumber(str) {
return str.match(/\b(\d+(\.\d+)?\b)/)[1];
}
function parseNumeric(numStr) {
return parseFloat(numStr);
}
function formatCurrency(num) {
return `$${num.toFixed(2)}`;
}.as-console-wrapper { top: 0; max-height: 100% !important; }
arr.reduceRight((p, c) => c(p), undefined);