Merge

Use the Merge node to combine data from two streams, once data of both streams is available.

Merge mode

You can specify how the Merge node should combine data from different branches. The following options are available:

Append

Keep data from both inputs. The output contains items from Input 1, followed by all items from Input 2.

Combine

Combine data from both inputs. Choose a Combination Mode to control how Mosaic Workflows merges the data.

Merge by fields

Compare items by field values. Enter the fields you want to compare in Fields to Match.

Mosaic Workflows's default behavior is to keep matching items. You can change this using the Output Type setting:

• Keep matches: merge items that match.
• Keep non-matches: merge items that don't match.
• Enrich Input 1: keep all data from Input 1, and add matching data from Input 2.
• Enrich Input 2: keep all data from Input 2, and add matching data from Input 1.

Field value clashes

If both items at an index have a field with the same name, this is a clash. For example, if all items in both Input 1 and Input 2 have a field named language, these fields clash. By default, Mosaic Workflows prioritizes Input 2, meaning if language has a value in Input 2, Mosaic Workflows uses that value when merging the items.

You can change this behavior:

1. Select Add Option > Clash Handling .
2. Choose which input to prioritize, or choose Always Add Input Number to Field Names to keep all fields and values, with the input number appended to the field name to show which input it came from.

Multiple matches

Matching by field can generate multiple matches if the inputs contain duplicate data. To handle this, select Add Option > Multiple Matches. Then choose:

• Include All Matches : output multiple items (one for each match).
• Include First Match Only : keep the first item, discard subsequent items.

Merge by position

Combine items based on their order. The item at index 0 in Input 1 merges with the item at index 0 in Input 2, and so on.

Inputs with different numbers of items

If there are more items in one input than the other, the default behavior is to leave out the items without a match. Choose Add Option > Include Any Unpaired Items to keep the unmatched items.

Field value clashes

If both items at an index have a field with the same name, this is a clash. For example, if all items in both Input 1 and Input 2 have a field named language, these fields clash. By default, Mosaic Workflows prioritizes Input 2, meaning if language has a value in Input 2, Mosaic Workflows uses that value when merging the items.

You can change this behavior:

1. Select Add Option > Clash Handling .
2. Choose which input to prioritize, or choose Always Add Input Number to Field Names to keep all fields and values, with the input number appended to the field name to show which input it came from.

Multiplex

Output all possible item combinations, while merging fields with the same name.

Field value clashes

If both items at an index have a field with the same name, this is a clash. For example, if all items in both Input 1 and Input 2 have a field named language, these fields clash. By default, Mosaic Workflows prioritizes Input 2, meaning if language has a value in Input 2, Mosaic Workflows uses that value when merging the items.

You can change this behavior:

1. Select Add Option > Clash Handling .
2. Choose which input to prioritize, or choose Always Add Input Number to Field Names to keep all fields and values, with the input number appended to the field name to show which input it came from.

Options

When combining branches, you can set Options:

For all modes:

• Clash handling : choose how to merge when branches clash, or when there are sub-fields.
• Fuzzy compare : whether to tolerate type differences when comparing fields (enabled), or not (disabled, default). For example, when you enable this, Mosaic Workflows treats "3" and 3 as the same.

When merging by field:

• Disable dot notation : this prevents accessing child fields using parent.child in the field name.
• Multiple matches : choose how Mosaic Workflows handles multiple matches when comparing branches.

When merging by position:

Include Any Unpaired Items: choose whether to keep or discard unpaired items.

Choose branch

Choose which input to keep. This option always waits until the data from both inputs is available. You can keep the data from Input 1 or Input 2, or you can output a single empty item. The node outputs the data from the chosen input, without changing it.

Merging branches with uneven numbers of items

The items passed into Input 1 of the Merge node will take precedence. For example, if the Merge node receives five items in Input 1 and 10 items in Input 2, it only processes five items. The remaining five items from Input 2 aren't processed.

Branch execution with If and Merge nodes

If you add a Merge node to a workflow containing an If node, it can result in both output branches of the If node executing.

The Merge node is triggered by one branch, then goes and executes the other branch.

For example, in the screenshot below there's a workflow containing a Edit Fields node, If node, and Merge node. The standard If node behavior is to execute one branch (in the screenshot, this is the true output). However, due to the Merge node, both branches execute, despite the If node not sending any data down the false branch.