Skip to main content

Constants and Variables

Constants and variables are, respectively, static and variable data that you can use in your BOps as arguments to modules. A good example of this would be to set a default state when an entity is created; It can be easily done with a constant.

Constants​

This is a property of a Business Operation. The data set in the constants cannot be changed and is accessible as a dependency in all the functions in the same Business Operation.

Variables​

"variables" is also a property of a Business Operation. The data set here can be changed by three functions: "increaseVariable", "decreaseVariable", and "setVariable", which we will talk about later in this same page. The variables can also be passed as dependencies for every module in the BOps it was declared.

Initializing Constants and Variables​

In order to initialize their values, we just need to specify to Meta-System what are their names, types, and initial value. Since both "constants" and "variables" are arrays, we should do it as the following:

// For Constants
{ "name": "your-constant-name", "type": "<TYPE_ENUM>", "value": "some value" }
// For Variables
{ "name": "your-constant-name", "type": "<TYPE_ENUM>", "initialValue": "some value" }
// the initialValue is optional

The property "type" can be one of the following values: "string", "date", "number", "boolean", "object", "array", "any". Of course, the value set of that constant or variable needs be of the same type declared.

Accessing Constants and Variables​

They can be accessed as a dependency for any modules of the BOps they were declared in. For more reference of how to do it, see the Dependencies documentation.

Setting The Value of Variables​

Meta-System provides three ways of setting a value of a variable, in the form of functions you can use in your BOps: "increaseVariable", "decreaseVariable", and "setVariable".

"increaseVariables"​

As the name suggests, it increases the value of a variable by 1. The variable to be modified needs to be a number.

You can require this function in your flow with "moduleType": "variable" and "moduleName": "increaseVariable".

Inputs​

You can pass any variable of number type as dependencies of this function. The input must follow this pattern:

{ "origin": "variable", "originPath": "<variableName>", "targetPath": "<variableName>" }

<variableName> should be replaced by the name set while initializing the variable.

Outputs​

There is only one output, and it is updatedCount, which a number representing the amount of variables increased by the function.

"decreaseVariables"​

It works similarly to the "increaseVariable" function, but this one decreases the value of the variable by 1. Both the inputs and outputs are the same.

"setVariables"​

This function sets the value of the variables to the provided arguments.

Inputs​

The dependencies of this function should have the origin and originPath pointing to the new value the variable should be set to. targetPath should be equal to the value of the variable.