Transaction Manager: Integrations - Handlebars syntax
Summarize
Summary of Transaction Manager: Integrations - Handlebars syntax
The Handlebars templating language allows administrators to create dynamic integration transformation templates. This lightweight language is essential for generating content based on specific data conditions and structures.
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Key Features
- Handlebars Expressions: Use double curly braces {{ }} to insert variables, functions, or properties. For example, {{user.name}} renders the user's name.
- Conditional Helpers: Control content rendering based on conditions using #if and #unless to display content for true or false conditions, respectively.
- Iteration Helpers: Utilize #each to loop through lists, and #with to change scope for accessing properties.
- Custom Helpers:
- zeroIfMissing: Ensures numerical fields have a default value, avoiding errors.
- lgkFilter: Filters items in a collection based on specified conditions.
- Whitespace Control: The tilde (~) manages whitespace to keep output clean and compact.
- Parent Context Reference: The @ symbol allows access to values from a higher scope, preventing confusion with local data.
Key Outcomes
By mastering Handlebars syntax, ServiceNow administrators can build flexible and maintainable integration templates, handle complex data requirements, and ensure accurate output formatting. This leads to improved efficiency and effectiveness in managing integrations.
You can use the Handlebars templating language when you build an integration transformation template.
Handlebars is a lightweight templating language used to generate dynamic content. Administrators building integration transformation templates use the following key elements of Handlebars syntax, together with enhancements specific to CPQ:
- Handlebars expressions: Enclosed in double curly braces {{ }}, expressions enable administrators to insert variables, functions, or properties into the template. For example, {{user.name}} renders the value of the name property of the user object.
- Built-in helpers include conditional helpers and iteration helpers.
- Conditional helpers enable you to render content conditionally based on a value. For example:
- #if renders content if the condition is true.
{{#if user.isActive}} Active {{/if}}This snippet renders "Active" only if
user.isActiveis true. - #unless – The opposite of #if, it renders content if the condition is false.
{{#unless user.isActive}} Inactive {{/unless}}This snippet renders "Inactive" if
user.isActiveis false.
- #if renders content if the condition is true.
- Iteration helpers let you loop through lists or modify scope.
- #each loops through an array and renders content for each item.
{{#each users}} <li>{{this.name}}</li> {{/each}}This snippet iterates through users and displays each user's name as a list item.
- #with changes the scope to a specific object.
{{#with user}} <p>{{name}}</p> {{/with}}This snippet simplifies access to properties of
userin the block.
- #each loops through an array and renders content for each item.
- Conditional helpers enable you to render content conditionally based on a value. For example:
Advanced Handlebars syntax for integrations
Here’s an explanation of each syntactical element used in the Integration Template, which leverages the Handlebars templating language.
- {{#if lines}} {{/if}}
{{#if}} checks whether something is true.
The following snippet checks whether there is something in
lines. Iflineshas a value (like a list of items or some data), it will do something inside the block. Iflinesis empty or doesn’t exist, it skips the block.{{#if lines}} We have lines to process! {{else}} No lines available. {{/if}}If
linesexists, it shows "We have lines to process!". If not, it shows "No lines available." - {{~#each lines~}} {{/each}}
{{#each}} repeats something for each item in a list.
The following snippet iterates over each item in the
lineslist and renders the content inside the block for every item. The ~ symbols are whitespace control characters in Handlebars. They help remove any extra spaces or line breaks before and after the block, ensuring cleaner and more compact output. (See below.){{~#each lines~}} <p>{{this}}</p> {{/each}}The snippet goes through each item in
linesand puts each item in a paragraph tag. - {{#if <logik line-level field varname>}} {{/if}}
{{#if <logik ...}} checks whether a specific piece of data is true or exists. It checks whether a specific field or value (like varname) in your data exists or is true. It's a way to check for specific information in a more complex structure (like in a dataset).
{{#if logik.lineLevelField.isActive}} The field is active! {{else}} The field is not active. {{/if}}This snippet checks whether
logik.lineLevelField.isActiveis true (like checking if something is "active"). If it is, it shows "The field is active!" If not, it shows "The field is not active."
The tilde (~)
The tilde (~), a control character, hides whitespace and line breaks, helping keep the output clean. It makes HTML more compact and prevents spacing issues in output.
In some of the examples above, a leading tilde before #each removes whitespace before the block starts. The trailing tilde after #each removes whitespace after the block starts.
The zeroIfMissing custom helper
The zeroIfMissing helper prevents errors due to missing values and ensures numerical fields always have a valid default value.
Custom Helper 'zeroIfMissing'
"price": {{zeroIfMissing txn.price}}, would become -> "price": 0 (or "price": 9.99, if txn.price is present)
The lgkFilter custom helper
The lgkFilter helper iterates through a collection and includes only items that meet a specified condition.
{
"numericFiltered": [
{{#lgkFilter lines "txn.line.custom.someNumber > 10"}}
{
"id": "{{txn.line.product.id}}",
"someNumber": "{{txn.line.custom.someNumber}}"
}
{{else}}
{
"error": "Item could not be added (numeric condition)"
}
{{/lgkFilter}}
],
"textFiltered": [
{{#lgkFilter lines "txn.line.custom.status == Active"}}
{
"id": "{{txn.line.product.id}}",
"status": "{{txn.line.custom.status}}"
}
{{else}}
{
"error": "Item could not be added (text condition)"
}
{{/lgkFilter}}
]
}
- Simple syntax: {{#lgkFilter lines "<predicate_field>"}}
- Conditional syntax: {{#lgkFilter lines "<predicate_field> <comparator> <literal_value>"}}
- Supported comparators: <, >, <=, >=, !=, ==
- Complex conditions such as && are not supported
The else block is supported within the helper.
The helper throws an error when its syntax is incorrect and when fields cannot be parsed.
The helper performs comma joins internally for valid JSON output.
The @ symbol
The @ ensures that you're pulling the value from the outer or parent context and not from the current context. It’s often used when the data you need is at a higher level in the structure, and you want to avoid confusing it with the local data of the current scope.
In the expression "LGK__TransactionId__c": "@{parentTransaction.id}", the @ symbol is used to reference a value from a parent context or object in templating systems, such as Handlebars or other similar systems.
The @{} syntax tells the system to look at the parent context (the object or data outside the current scope) and retrieve the value of parentTransaction.id.
For example, suppose you have an object like this:
{
"parentTransaction": {
"id": "12345"
}
}
When you use "LGK__TransactionId__c": "@{parentTransaction.id}", the id from parentTransaction (which is 12345) will be used as the value for
"LGK__TransactionId__c".
Conditional assignment example
The line "LGK__ParentTransactionLineId__c": {{#if txn.line.custom.parentLineReferenceId}} "@{line_{{txn.line.custom.parentReferenceId}}.id}" {{else}} null {{/if}} is part of a Handlebars template and conditionally
sets the value of the field LGK__ParentTransactionLineId__c.
LGK__ParentTransactionLineId__cis the key where the resulting value will be placed.- {{#if txn.line.custom.parentLineReferenceId}} checks whether
txn.line.custom.parentLineReferenceIdexists and has a value. - @{line_{{txn.line.custom.parentReferenceId}}.id} creates a dynamic reference to the
idof a specific line based onparentReferenceId. - {{else}} null {{/if}} sets the value to null if the condition is false.
Concatenating Salesforce fields with conditional punctuation
In Handlebars, concatenating multiple fields together with punctuation (like commas, spaces, and conditional checks) can be done by combining variables in the template and using {{#if}} blocks to handle conditional logic.
For example, you can use the following approach to concatenate fields such as street address, street address2, city, state, and zip code for an address while ensuring that a comma and space after street address2 are only included if street address2 is populated:
{{#if streetAddress}}
{{streetAddress}}
{{#if streetAddress2}}, {{streetAddress2}}{{/if}}
{{#if city}}, {{city}}{{/if}}
{{#if state}}, {{state}}{{/if}}
{{#if zipcode}}, {{zipcode}}{{/if}}
{{else}}
No address available
{{/if}}
This concatenates fields like streetAddress, streetAddress2, and city, ensuring that commas are only included when the corresponding fields are populated.
Example output with streetAddress2: "123 Main St, Apt 4, San Francisco, CA, 94105"
Example output without streetAddress2: "123 Main St, San Francisco, CA, 94105"
Conclusion
By using these key elements, administrators can create dynamic, flexible, and maintainable integration transformation templates. Understanding and leveraging expressions, helpers, blocks, conditionals, and parent context references enables handling complex data and logic with ease.