Introduction

Activity blocks in Studio Pro require you to specify certain parameters in order to perform the action correctly. These can be input boxes, buttons, radio buttons, checkboxes or drop-down lists.

Parameters that are mandatory for an activity are indicated by a red asterisk (*). If the mandatory parameter is not pecified, then:

1. When you deselect the activity block, an unfilled parameter will get highlighted in the parameter section, and the "!" symbol will appears in the activity block.
2. The workflow will not be executed. 

Depending on the function to be performed, the activity parameters may differ.

In this article we will review the principles of the basic parameters and examples of their use.

Assigning a certain value

Many activities involve assigning a value to a parameter. For example, in the Input to desktop app activity, you must specify the text you want to enter.

Most frequently, when setting a value, you must select one of three options:

1. Set a value
2. Calculate a value
3. Save the previous step result

Let's take a closer look at these options.

Set a value

This option means that anything entered in the "Value" field will be interpreted as a string or number. For example, if you type The city of New York, the value will automatically be interpreted as a string (text). If you write a number, such as 123, the value will be interpreted as a number.

The table below shows some examples of interpretations.

Calculate a value

This option allows you to calculate a value using JavaScript syntax.

For example, if you set the contragent_exists variable to true, then the variable will take the boolean type and value true. If you write "The city of New York" in the city variable, it will become a string.

The table below shows the results for the same examples as in the previous table.

If you use the "Calculate a value" option, it is also possible to use additional libraries - lodash, moment.js and mustache:

//Examples of references to lodash, moment, mustache
_.has(); //lodash
moment().add(); //moment
mustache.render(); //mustache

Set the previous step result

If the "Save the previous step result" option is selected, the value returned by the activity from the previous step will be used as the value (if the activity does not return a result, the value will not be written).

Suppose we need to read a text from a file (without changing it in any way) and send an email containing this text. The algorithm will look like this:

This simple workflow contains two activities:

1. Read text file - this activitiy reads the text from a file.
2. Send email - this activity sends an email. It takes the text read from the file as the body of the email, since we select the "Save the previous step result" option in the "Mail body" parameter.