Building Apps with Jigx

Expressions

7min

With expressions, you can structure and manipulate data before binding the data to the UI components. Expressions are JSONata language-based. JSONata is a lightweight query and transformation language for JSON data. JSONata is a rich complement of built-in operators and functions providing options to manipulate and combine data.
﻿
Shared expressions
The shared expressions can be set either in the index.jigx file or in the ﻿ itself. The expressions property is used for this and allows you to choose a custom name for the expression and save a value.
Expressions set in the index.jigx
Expressions that are set in the index.jigx are reusable throughout your whole solution. 
index.jigx
expressions.jigx
title: jigx-samples
name: jigx-samples

expressions:
  lat: =@ctx.system.geolocation.coords.latitude
  lng: =@ctx.system.geolocation.coords.longitude
title: jigx-samples
name: jigx-samples

expressions:
  lat: =@ctx.system.geolocation.coords.latitude
  lng: =@ctx.system.geolocation.coords.longitude
﻿
Expressions set inside the jig
These expressions are only available in the ﻿ itself.
YAML
datasource.jigx
title: Shared expressions example
type: jig.default

expressions:
  numberOfEmployees: =$count(@ctx.datasources.employee-list.id)
  address: =@ctx.datasources.employee-detail.street & ', ' &   @ctx.datasources.employee-detail.county & ', ' & @ctx.datasources.employee-detail.city
  employee: =@ctx.datasources.employee-detail.name & ' ' & @ctx.datasources.employee-detail.surname & ', ' & @ctx.datasources.employee-detail.position 
  
  
children:
  - type: component.entity
    options:
      isCompact: true
      children:
        - type: component.section
          options:
            title: All Employees
            children:
              - type: component.entity-field
                options:
                  label: Number of Employees
                  value: =@ctx.expressions.numberOfEmployees
        - type: component.section
          options:
            title: Employee detail
            children:
              - type: component.entity-field
                options:
                  label: Employee
                  value: =@ctx.expressions.employee
              - type: component.entity-field
                options:
                  label: Employee address
                  value: =@ctx.expressions.address
title: Shared expressions example
type: jig.default

expressions:
  numberOfEmployees: =$count(@ctx.datasources.employee-list.id)
  address: =@ctx.datasources.employee-detail.street & ', ' &   @ctx.datasources.employee-detail.county & ', ' & @ctx.datasources.employee-detail.city
  employee: =@ctx.datasources.employee-detail.name & ' ' & @ctx.datasources.employee-detail.surname & ', ' & @ctx.datasources.employee-detail.position 
  
  
children:
  - type: component.entity
    options:
      isCompact: true
      children:
        - type: component.section
          options:
            title: All Employees
            children:
              - type: component.entity-field
                options:
                  label: Number of Employees
                  value: =@ctx.expressions.numberOfEmployees
        - type: component.section
          options:
            title: Employee detail
            children:
              - type: component.entity-field
                options:
                  label: Employee
                  value: =@ctx.expressions.employee
              - type: component.entity-field
                options:
                  label: Employee address
                  value: =@ctx.expressions.address
﻿
Expression structure 
Using IntelliSense in ﻿ shows where and when you can add an expression by displaying the =$ or =@ctx. In ﻿expressions alwasy start with =. ﻿ converts @ctx. to $$. when executing expressions in jsonata.
Adding an empty array index [] in the path forces jsonata to return an array of one item versuses the normal behavior where it returns the item directly.
Text
=@ctx.datasources.value
[{}] => {}
[{},{}] => [{},{}]

=@ctx.datasources.value[]
[{}] => [{}] ← notice array of one
[{},{}] => [{},{}]
=@ctx.datasources.value
[{}] => {}
[{},{}] => [{},{}]

=@ctx.datasources.value[]
[{}] => [{}] ← notice array of one
[{},{}] => [{},{}]
﻿
Expressions can be used in many ways when creating apps, here are common use cases:
Use
Description
Example
datasource 
To call data from a datasource 
=@ctx.datasource.mydata.datacolumn
component
Used inside a component to reference data in that component  
=@ctx.component.state.value
components
Used in a ﻿ to reference data from various components in that ﻿﻿
=@ctx.components.list.state.filter
current item
Use data in the current component
=@ctx.current.item.value
jig
Pull data in from another ﻿﻿
=@ctx.jig.inputs.jigname.description
jigs
Pull data in from multiple ﻿s
=@ctx.jigs.
organization
Reference the name or id of the ﻿ organization﻿﻿
=@ctx.organization.name
solution
Reference the ﻿ solution﻿﻿
=@ctx.solution.name
system
Get data about various system﻿ values such as offline status
=@ctx.system.isOffline
user
Reference data about the current ﻿ user﻿﻿
=@ctx.user.displayName
Expression examples
Expressions are a powerful and flexible way to transform and extract data for use in a ﻿. Below are links to examples showing how JSONata expressions can be used when creating apps. 
JSONata expressions
Example of use
﻿Aggregation﻿﻿
To return minimum, maximum or an average value in an array.
﻿Boolean﻿﻿
Evaluate data to find a true or false result.
﻿Comparison Operators﻿﻿
Compare values in data and use the value in a conditional logical expression, e.g., is an amount greater than 100.
﻿Date & Time﻿﻿
Return a date and time in various formats, e.g., ISO 8601. 
﻿Path Operators﻿﻿
Navigate and access specific elements or properties within a data set, e.g., for filtering or searching. 
﻿Functional Programming﻿﻿
Compare values or display data based on certain conditions and using logical statements, e.g., adding HTML variable in content, or a multi-select as a functionParameter.
﻿Jigx Variables﻿﻿
﻿﻿ variable set used in expressions to manipulate data specific to a ﻿, e.g., determining the logged-in user, or the organization and solution.  
﻿Predicate Queries﻿﻿
Used for query refinement.
﻿String﻿﻿
There are many uses for using string expressions, these can be to concatenate two strings to display multiple data records in one row or write numbers as strings, or select only a few characters from the whole string.
See Also
﻿Advanced Expressions﻿﻿
﻿Expressions - cheatsheet﻿﻿
﻿Examples ﻿﻿
﻿

Updated 30 Oct 2023

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Static Data

Advanced Expressions

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TABLE OF CONTENTS

Shared expressions

Expressions set in the index.jigx

Expressions set inside the jig

Expression structure

Expression examples

Use	Description	Example
datasource	To call data from a datasource	=@ctx.datasource.mydata.datacolumn
component	Used inside a component to reference data in that component	=@ctx.component.state.value
components	Used in a to reference data from various components in that	=@ctx.components.list.state.filter
current item	Use data in the current component	=@ctx.current.item.value
jig	Pull data in from another	=@ctx.jig.inputs.jigname.description
jigs	Pull data in from multiple s	=@ctx.jigs.
organization	Reference the name or id of the organization	=@ctx.organization.name
solution	Reference the solution	=@ctx.solution.name
system	Get data about various system values such as offline status	=@ctx.system.isOffline
user	Reference data about the current user	=@ctx.user.displayName

JSONata expressions	Example of use
Aggregation	To return minimum, maximum or an average value in an array.
Boolean	Evaluate data to find a true or false result.
Comparison Operators	Compare values in data and use the value in a conditional logical expression, e.g., is an amount greater than 100.
Date & Time	Return a date and time in various formats, e.g., ISO 8601.
Path Operators	Navigate and access specific elements or properties within a data set, e.g., for filtering or searching.
Functional Programming	Compare values or display data based on certain conditions and using logical statements, e.g., adding HTML variable in content, or a multi-select as a functionParameter.
Jigx Variables	variable set used in expressions to manipulate data specific to a , e.g., determining the logged-in user, or the organization and solution.
Predicate Queries	Used for query refinement.
String	There are many uses for using string expressions, these can be to concatenate two strings to display multiple data records in one row or write numbers as strings, or select only a few characters from the whole string.