Function filterTransform

src/expression/transform/filter.transform.js:18–49

* Attach a transform function to math.filter * Adds a property transform containing the transform function. * * This transform adds support for equations as test function for math.filter, * so you can do something like 'filter([3, -2, 5], x > 0)'.

(args, math, scope)

   * so you can do something like 'filter([3, -2, 5], x > 0)'.
   */
  function filterTransform (args, math, scope) {
    const filter = createFilter({ typed })
    const transformCallback = createTransformCallback({ typed })

    if (args.length === 0) {
      return filter()
    }
    let x = args[0]

    if (args.length === 1) {
      return filter(x)
    }

    const N = args.length - 1
    let callback = args[N]

    if (x) {
      x = _compileAndEvaluate(x, scope)
    }

    if (callback) {
      if (isSymbolNode(callback) || isFunctionAssignmentNode(callback)) {
        // a function pointer, like filter([3, -2, 5], myTestFunction)
        callback = _compileAndEvaluate(callback, scope)
      } else {
        // an expression like filter([3, -2, 5], x > 0)
        callback = compileInlineExpression(callback, math, scope)
      }
    }

    return filter(x, transformCallback(callback, N))
  }
  filterTransform.rawArgs = true

  function _compileAndEvaluate (arg, scope) {