Advanced JEXL

Unary Operators

Example

Below code means false by negate operation.

    {{!true}}

Binary Operators

Comparisons

A note about in

The in operator can be used to check for a substring: "Cad" in "Ron Cadillac", and it can be used to check for an array element: "coarse" in ['fine', 'medium', 'coarse']. However, the == operator is used behind-the-scenes to search arrays, so it should not be used with arrays of objects. The following expression returns false: {a: 'b'} in [{a: 'b'}].

Ternary operator

Conditional expressions check to see if the first segment evaluates to a truthy value. If so, the consequent segment is evaluated. Otherwise, the alternate is. If the consequent section is missing, the test result itself will be used instead.

Native Types

Groups

Parentheses work just how you'd expect them to:

Identifiers

Access variables in the context object by just typing their name. Objects can be traversed with dot notation, or by using brackets to traverse to a dynamic property name.

Example context:

{
  name: {
    first: "Malory",
    last: "Archer"
  },
  exes: [
    "Nikolai Jakov",
    "Len Trexler",
    "Burt Reynolds"
  ],
  lastEx: 2
}

Functions

In JEXL, common built-in functions are provided, but also functions library is extended with lodash functions.

You can use lodash functions from this link.

Also you can check our functions from this article.

Example

Check JEXL codes below

Find Min

    {{ min([65, 42, 87, 88]) }}

    // => 42

Reverse Array

    {{ reverse([1, 2, 3, 4]) }}

    // => [4, 3, 2, 1]

Check Equal

    {{ eq({ a:1 }, { a:1 }) }}
    // => true

    {{ eq(3, 4) }}
    // => false

Add Elements To Array

    {{ concat([1], 2, 3, 4) }}

    // => [1, 2, 3, 4]

Get Last Element of Array

    {{ reverse([1, 2, 3]) }}

    // => 3