Expression Evaluator#

The Expression Evaluator task is one of the most powerful tasks shipped by default. It can be used to make several operations upon inputs in order to generate an output. It can make operations using the mathjs engine, XPath and Regular Expressions, it can also be used to evaluate expressions until one of the outputs evaluates a Boolean true result (as with the "if (condition) else" statement).

Warning

This task is currently deprecated and will be removed in future versions.

Inputs#

Name	Data Type	IsTrigger	Description
`<custom list>`	`<custom>`	Yes	Type of value to perform operations in order to generate an output
Activate	`any`	Yes	Activates the task

Outputs#

Name	Data Type	Description
`<custom list>`	`<custom>`	Type of value to perform operations in order to generate an output
Error	`Error`	Error that occurred during the processing of this task

Settings#

On the General Tab, you have the usual settings and the following setting:

Name	Data Type	Values	Default Value	Description
Expression Type	`enum`	`Generic` `XPath` `RegularExpression`	`Generic`	Types of expression it can evaluate
Evaluator Behavior	`enum`	`EvaluateAll` `EvaluateUntilTrue`	`EvaluateAll`	Different types of logic the task can have when evaluating the expression
Clear Inputs	`Boolean`		false	After being triggered resets the inputs

On the Inputs Tab you have the following setting:

Name	Data Type	Description
Name	`String`	Input Name.
Type	`Long` `Decimal` `DateTime` `Boolean` `String` `Integer`	The type of input value.
Collection Type	`None` `Array` `Map`
Default Value	`any`	The default value of an input parameter.

On the Outputs Tab you have the following setting:

Name	Data Type	Description
Name	`String`	Output Name.
Type	`Long` `Decimal` `DateTime` `Boolean` `String` `Integer`	The type of output value.
Collection Type	`None` `Array` `Map`
Expression	`any`	The operation you wish to apply to the input.

Note

For testing you also have an Input. You can try with a dummy input values and evaluate your expression.

Behavior#

The Generic Type will use the mathjs engine, which is a math library for javascript, and can therefore use math operations as well as some native javascript. The XPath type searches in the given object for the path and returns the value or array of values that corresponds to said path. The Regular Expression type applies a regular expression to the input value and returns the value or array of values that corresponds to the result of the expression. The Clear Inputs, if true, will reset the inputs after the task is triggered. The EvaluateUntilTrue when the expression returns a true value will output the first value as true, in opposition to the EvaluateAll that will evaluate every expression output and emit all the values.

Tip: You can test your mathjs expression at https://jsbin.com/devacu/edit?html,js,output , you can also see the documentation of what's available at http://mathjs.org/docs/expressions/syntax.html and at http://mathjs.org/docs/reference/functions.html ⧉ .

Remarks#

This task is a very powerful tool for operations to an input value and mathjs has several typical javascript functions, but mathjs is not a javascript engine, so native javascript code may or may not work on the mathjs engine.