Module that helps you write generated functions in Node
npm install generate-function
Writing code that generates code is hard. You should only use this if you really, really, really need this for performance reasons (like schema validators / parsers etc).
var genfun = require('generate-function') var addNumber = function(val) { var fn = genfun() ('function add(n) {') ('return n + %d', val) // supports format strings to insert values ('}') return fn.toFunction() // will compile the function } var add2 = addNumber(2) console.log('1+2=', add2(1)) console.log(add2.toString()) // prints the generated function
If you need to close over variables in your generated function pass them to toFunction(scope)
var multiply = function(a, b) { return a * b } var addAndMultiplyNumber = function(val) { var fn = genfun() ('function(n) {') ('if (typeof n !== "number") {') // ending a line with { will indent the source ('throw new Error("argument should be a number")') ('}') ('var result = multiply(%d, n+%d)', val, val) ('return result') ('}') // use fn.toString() if you want to see the generated source return fn.toFunction({ multiply: multiply }) } var addAndMultiply2 = addAndMultiplyNumber(2) console.log('(3 + 2) * 2 =', addAndMultiply2(3))
See generate-object-property if you need to safely generate code that can be used to reference an object property
MIT