Merging Data

1. How the Merge Action Works#

The Merge block takes a list of values or variables and merges them together. The type of merging performed depends on the types of the inputs:

• Arrays: If multiple arrays are provided, they are concatenated into a single flat array.
• Objects: If multiple objects are provided, their properties are combined into a single object. If there are overlapping keys, the properties from the object provided later in the list will overwrite those from earlier objects.
• Mixed/Primitives: If a mix of arrays, objects, or primitive values is provided, they are typically gathered into an array, or handled according to the specific context.

Configuration Options#

• Value: A comma-separated list of values or variables to merge. You can reference variables using the {$variableName} syntax or access the output of the previous block using {$block.output}.
• Target Variable: (Optional) The name of a new or existing variable where the merged result will be stored. If left blank, the merged result is available in block.output for the immediate next step.

2. Basic Examples#

Merging Arrays#

Suppose you have scraped two lists of products and stored them in variables:

• productsPage1: [{"id": 1, "name": "Item A"}, {"id": 2, "name": "Item B"}]
• productsPage2: [{"id": 3, "name": "Item C"}]

To combine these:

• Action: merge
• Value: {$productsPage1}, {$productsPage2}
• Target Variable: allProducts

The allProducts variable will now contain: [{"id": 1, "name": "Item A"}, {"id": 2, "name": "Item B"}, {"id": 3, "name": "Item C"}]

Merging Objects#

Suppose you have extracted user profile data in two steps:

• basicInfo: {"name": "Alice", "role": "Admin"}
• contactInfo: {"email": "alice@example.com", "phone": "555-1234"}

To combine these into a single profile object:

• Action: merge
• Value: {$basicInfo}, {$contactInfo}
• Target Variable: userProfile

The userProfile variable will now contain: {"name": "Alice", "role": "Admin", "email": "alice@example.com", "phone": "555-1234"}

3. Using the Previous Output#

Often, you might want to merge the result of the immediately preceding block with existing data.

For example, if the previous block fetched additional details for an item, and you want to merge it with a base item stored in currentItem:

• Action: merge
• Value: {$currentItem}, {$block.output}
• Target Variable: currentItem

This will effectively update currentItem with the newly fetched details.

4. Combining with Other Actions#

The Merge action is commonly used in conjunction with looping structures like For Each or While.

A typical pattern for gathering data across a loop is:

1. Initialize an empty array variable before the loop (e.g., set action: allData = []).
2. Inside the loop, extract some data (e.g., using a JavaScript block or API call).
3. Use a Merge block inside the loop to append the new data to the accumulator array:
   • Value: {$allData}, {$block.output}
   • Target Variable: allData

By effectively using the Merge block, you can easily organize and structure the data collected throughout your automated tasks.