Node.js bindings for ExprTk
ExprTk.js supports both synchronous and asynchronous background execution of thunks precompiled from a string including asynchronous and multithreaded versions of TypedArray.prototype.map and TypedArray.prototype.reduce and a synchronous multi-threaded version of TypedArray.prototype.map.
Its main advantage is that it allows deferring of heavy computation for asynchronous execution in a background thread - something that Node.js/V8 does not allow without the very complex mechanisms of worker_threads.
Even in single-threaded synchronous mode ExprTk.js outperforms the native JS TypedArray.prototype.map running in V8 by a significant margin for all types and array sizes and it comes very close to a direct iterative for loop.
It also supports being directly called from native add-ons, including native threads, without any synchronization with V8, allowing JS code to drive multi-threaded mathematical transformations.
npm install exprtk.js
const Float64Expression = require('exprtk.js').Float64;
const expr = new Float64Expression('(a + b) / 2');
const inputArray = new Float64Array(1e6);
// Happens in a background thread, iterates over 'a', with b=4
const outputArray = await expr.mapAsync(inputArray, 'a', { 'b': 4 });
// or with 4 threads on 4 cores
const outputArray = await expr.mapAsync(4, inputArray, 'a', { 'b': 4 });
Refer to the ExprTk manual for the full expression syntax.