Expressions
Predicate Queries

3min
Use JSONata Predicate Queries at any location path; the selected items can be filtered using a predicate - <expr> where expr evaluates to a Boolean value. With that, you can select values from the array based on the specific type set as the predicate expression.
Configuration
Result
Expression
Evaluate if true and show the name
=@ctx.datasources.mydata[title='Nurse' and color='blue'].name
Be careful when using complex expressions, such as expressions that iterate one datasource across another, as your solution performance could become slower. To avoid this, try to use the datasource queries to get the desired result rather than an expression.
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﻿Examples and code snippets ﻿
Predicate queries
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In this example the expression is used to show the name of the nurse whose color is blue. 
See the full code sample in GitHub. 
expression.jigx
datasources:
  mydata: 
    type: datasource.static
    options:
      data:
        - name: Jane Stevens
          title: Doctor
          email: jane@first.com
          number: 0.64734
          number2: 12
          color: blue
          time: '2021-11-07T15:07:54.972Z'
          array: [5,1,2,3,7,9]
        - name: Arthur Marks
          title: Nurse
          email: arthur@first.com
          number: 0.98
          number2: 10
          color: red
          time: '2021-11-07T15:07:54.972Z'
          array: [5,1,2,3,7,9]
        - name: Merley Shanks
          title: Nurse
          email: merley@first.com
          number: 0.43
          number2: 9
          color: blue
          time: '2021-11-07T15:07:54.972Z'
          array: [5,1,2,3,7,9]
children:
  - type: component.entity
    options:
      children:
        - type: component.entity-field
          options:
            label: Predicate expression
            value: =@ctx.datasources.mydata[title='Nurse' and color='blue'].name
datasources:
  mydata: 
    type: datasource.static
    options:
      data:
        - name: Jane Stevens
          title: Doctor
          email: jane@first.com
          number: 0.64734
          number2: 12
          color: blue
          time: '2021-11-07T15:07:54.972Z'
          array: [5,1,2,3,7,9]
        - name: Arthur Marks
          title: Nurse
          email: arthur@first.com
          number: 0.98
          number2: 10
          color: red
          time: '2021-11-07T15:07:54.972Z'
          array: [5,1,2,3,7,9]
        - name: Merley Shanks
          title: Nurse
          email: merley@first.com
          number: 0.43
          number2: 9
          color: blue
          time: '2021-11-07T15:07:54.972Z'
          array: [5,1,2,3,7,9]
children:
  - type: component.entity
    options:
      children:
        - type: component.entity-field
          options:
            label: Predicate expression
            value: =@ctx.datasources.mydata[title='Nurse' and color='blue'].name
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Result	Expression
Evaluate if true and show the name	=@ctx.datasources.mydata[title='Nurse' and color='blue'].name
Updated 31 Jul 2023
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Path Operators
String
Predicate Queries

Configuration

﻿Examples and code snippets ﻿

Examples and code snippets
