Repeat and conditionally show blocks

Directives expand or omit child blocks when a template compiles. Add a Directive from the toolbox and configure it in the editor; they are not inline Handlebars tags.

Repeat an array

Add sample data

Add an items array to the template’s Sample Data:

{
  "order_id": "ORD-123",
  "items": [
    { "name": "Laptop", "quantity": 1 },
    { "name": "Mouse", "quantity": 2 }
  ]
}

Configure the container

Add a Directive block, select each, and set Array Path to items, without placeholder braces. Add a Section as its child.

Write the repeating content

{{@index + 1}}. {{this.name}} — {{this.quantity}} for order {{order_id}}

Preview with zero, one, and several items. The root order_id remains available inside the loop.

Set Max Blocks to limit repeated content and Overflow Text to a message such as and {remaining} more items. The overflow token has a single pair of braces. Each item can generate multiple blocks, so also check the total compiled message against limits. An empty array produces no repeated children. A missing or non-array source is an error; supply [] when there are no items.

Show content conditionally

Select if, specify a condition path, and choose an operator. The true branch is children; message templates can also supply elseChildren. Set negate: true to invert the result.

Operator	Matches when
`truthy`	The value is truthy; false, zero, empty string, null, and missing values do not match
`equals`, `not_equals`	The value matches or differs from `compareValue`; numeric strings compare numerically
`exists`, `not_exists`	A value is present or absent; null counts as absent
`greater_than`, `less_than`	Numeric comparison with `compareValue`
`contains`	A string contains the comparison text, case-insensitively, or an array contains an exact stringified item
`is_empty`	Missing, null, whitespace-only string, empty array, or empty object

Comparison operators need compareValue. Non-numeric values for a numeric comparison produce an error. This complete block shows different content for an approved request:

{
  "type": "directive_container",
  "directive_type": "if",
  "directive_config": {
    "condition": "status",
    "operator": "equals",
    "compareValue": "approved"
  },
  "children": [
    { "type": "section", "text": { "type": "mrkdwn", "text": "Approved" } }
  ],
  "elseChildren": [
    { "type": "section", "text": { "type": "mrkdwn", "text": "Awaiting approval" } }
  ]
}

Use sample data { "status": "approved" } and then { "status": "pending" } to exercise both branches.

Modal directives have a narrower contract: modal if checks a truthy dot path and does not support the message operator table or elseChildren. Validate modals separately. The editor’s organizational block directive is disabled; use each and if for editor-authored workflows.

Nested containers

A child container can reference data available in its parent context. Keep nesting shallow, use explicit paths, and test the expanded result. An inner loop replaces this with its own item; do not assume this still points at the outer item. For API authoring, read GET /v1/templates/block-schema and run POST /v1/templates/validate before saving. See API authoring and template design.

Templates

Data and reuse

Build an example

Repeat and conditionally show blocks

Repeat an array

Show content conditionally

Nested containers

​Repeat an array

​Show content conditionally

​Nested containers

Repeat an array

Show content conditionally

Nested containers