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Conditional Functions

In this section, various conditional functions will be explored, which are available for use in PubSubDB mapping rules. The functions are designed to facilitate the manipulation and transformation of data using conditional operations during the mapping process. These functions are adapted from the ConditionalHandler class, and are implemented as a functional system referred to as @pipes.

Table of Contents

conditional.ternary

The conditional.ternary function evaluates a condition and returns one of the two provided values based on the result of the condition. It takes three parameters: the condition to evaluate, the value to return if the condition is true, and the value to return if the condition is false.

Example

Suppose there are the following input JSON objects:

Object A:

{
  "data": {
    "isActive": true,
    "activeLabel": "Active",
    "inactiveLabel": "Inactive"
  }
}

The goal is to create a new object with the label based on the isActive value. The conditional.ternary function can be used in the mapping rules as follows:

status_label:
  "@pipe":
    - ["{a.data.isActive}", "{a.data.activeLabel}", "{a.data.inactiveLabel}"]
    - ["{@conditional.ternary}"]

After executing the mapping rules, the resulting JSON object will be:

{
  "status_label": "Active"
}

conditional.equality

The conditional.equality function checks whether two values are equal, using non-strict equality (==). It takes two parameters: the first value (value1) and the second value (value2).

Example

Suppose there are the following input JSON objects:

Object A:

{
  "data": {
    "value1": 42,
    "value2": "42"
  }
}

The goal is to create a new object with a boolean value indicating whether value1 and value2 are equal. The conditional.equality function can be used in the mapping rules as follows:

are_values_equal:
  "@pipe":
    - ["{a.data.value1}", "{a.data.value2}"]
    - ["{@conditional.equality}"]

After executing the mapping rules, the resulting JSON object will be:

{
  "are_values_equal": true
}

conditional.strict_equality

The conditional.strict_equality function checks whether two values are equal, using strict equality (===). It takes two parameters: the first value (value1) and the second value (value2).

Example

Suppose there are the following input JSON objects:

Object A:

{
  "data": {
    "value1": 42,
    "value2": "42"
  }
}

The goal is to create a new object with a boolean value indicating whether value1 and value2 are strictly equal. The conditional.strict_equality function can be used in the mapping rules as follows:

are_values_strictly_equal:
  "@pipe":
    - ["{a.data.value1}", "{a.data.value2}"]
    - ["{@conditional.strict_equality}"]

After executing the mapping rules, the resulting JSON object will be:

{
  "are_values_strictly_equal": false
}

conditional.greater_than

The conditional.greater_than function checks whether the first value is greater than the second value. It takes two parameters: the first number (value1) and the second number (value2).

Example

Suppose there are the following input JSON objects:

Object A:

{
  "data": {
    "value1": 42,
    "value2": 30
  }
}

The goal is to create a new object with a boolean value indicating whether value1 is greater than value2. The conditional.greater_than function can be used in the mapping rules as follows:

is_value1_greater_than_value2:
  "@pipe":
    - ["{a.data.value1}", "{a.data.value2}"]
    - ["{@conditional.greater_than}"]

After executing the mapping rules, the resulting JSON object will be:

{
  "is_value1_greater_than_value2": true
}

conditional.less_than

The conditional.less_than function checks whether the first value is less than the second value. It takes two parameters: the first number (value1) and the second number (value2).

Example

Suppose there are the following input JSON objects:

Object A:

{
  "data": {
    "value1": 42,
    "value2": 50
  }
}

The goal is to create a new object with a boolean value indicating whether value1 is less than value2. The conditional.less_than function can be used in the mapping rules as follows:

is_value1_less_than_value2:
  "@pipe":
    - ["{a.data.value1}", "{a.data.value2}"]
    - ["{@conditional.less_than}"]

After executing the mapping rules, the resulting JSON object will be:

{
  "is_value1_less_than_value2": true
}

conditional.greater_than_or_equal

The conditional.greater_than_or_equal function checks whether the first value is greater than or equal to the second value. It takes two parameters: the first number (value1) and the second number (value2).

Example

Suppose there are the following input JSON objects:

Object A:

{
  "data": {
    "value1": 42,
    "value2": 42
  }
}

The goal is to create a new object with a boolean value indicating whether value1 is greater than or equal to value2. The conditional.greater_than_or_equal function can be used in the mapping rules as follows:

is_value1_greater_than_or_equal_value2:
  "@pipe":
    - ["{a.data.value1}", "{a.data.value2}"]
    - ["{@conditional.greater_than_or_equal}"]

After executing the mapping rules, the resulting JSON object will be:

{
  "is_value1_greater_than_or_equal_value2": true
}

conditional.less_than_or_equal

The conditional.less_than_or_equal function checks whether the first value is less than or equal to the second value. It takes two parameters: the first number (value1) and the second number (value2).

Example

Suppose there are the following input JSON objects:

Object A:

{
  "data": {
    "value1": 42,
    "value2": 42
  }
}

The goal is to create a new object with a boolean value indicating whether value1 is less than or equal to value2. The conditional.less_than_or_equal function can be used in the mapping rules as follows:

is_value1_less_than_or_equal_value2:
  "@pipe":
    - ["{a.data.value1}", "{a.data.value2}"]
    - ["{@conditional.less_than_or_equal}"]

After executing the mapping rules, the resulting JSON object will be:

{
  "is_value1_less_than_or_equal_value2": true
}