expression-evaluator

JavaScript (TypeScript) math expression evaluator library

How to compile this repo

• git clone https://github.com/tsv2013/expression-evaluator.git
• cd expression-evaluator
• npm i
• npm test
• npm run build

Sample usage

Basic functions

  var ee = new ExpressionEvaluator();
  var res1 = ee.evaluate("6 / 2 + 1 + 2*2 - 5");
  var res2 = ee.evaluate("false or false");

Custom functions

  ExpressionEvaluator.operations["myFunc"] = {
    priority: 100,
    function: (a, b) => (a+b)/2
  }
  ExpressionEvaluator.operations["mySq"] = {
    priority: 100,
    function: a => a*a
  }
  ExpressionEvaluator.operations["mySecond"] = {
    priority: 100,
    function: (a, b, c) => b
  }
  var ee = new ExpressionEvaluator();
  var result = ee.evaluate("mySecond(5, myFunc(2,4), mySq(2))");

Evaluation context

  var ee = new ExpressionEvaluator();
  var evaluationContext = { propertyName: 1 };
  var result = ee.evaluate("{propertyName} + 1", evaluationContext);