DataWeave Patterns

Production-ready DataWeave 2.x patterns for MuleSoft developers — copy, paste, transform.

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Who Is This For?

• MuleSoft developers looking for battle-tested DataWeave snippets
• Integration architects who need proven transformation patterns for enterprise mappings
• Teams migrating from DW 1.0 to 2.0 — see our migration guide
• Anyone studying for MuleSoft certification — real-world examples, not toy data

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What's Inside

• 50 DataWeave patterns across 10 categories — each with realistic input/output, working code, and alternative syntax
• DW 2.x Cheatsheet — comprehensive quick-reference (PDF)
• Anti-Patterns Guide — 12 common mistakes and how to fix them
• DW 1.0 → 2.0 Migration Guide — side-by-side syntax changes
• Playground Tips — test any pattern in MuleSoft's online playground

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Quick Start

1. Pick a pattern from the table of contents below.

2. Copy the code into your Mule project or the DataWeave Playground.

3. Try it — here's a working example you can paste right now:

%dw 2.0
output application/json
---
// Group employees by department, then count per group
payload groupBy $.department
    mapObject ((employees, dept) -> {
        (dept): sizeOf(employees)
    })

// Input:  [{"name":"Alice","department":"Eng"},{"name":"Bob","department":"Sales"},{"name":"Carol","department":"Eng"}]
// Output: {"Eng": 2, "Sales": 1}

No install. No dependencies. Just working DataWeave.

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Table of Contents

Patterns by Category

#	Category	Patterns	Difficulty Range
01	Array Manipulation	8 patterns	Beginner → Advanced
02	Object Transformation	6 patterns	Beginner → Advanced
03	String Operations	5 patterns	Beginner → Intermediate
04	Type Coercion	4 patterns	Beginner → Advanced
05	XML Handling	5 patterns	Intermediate → Advanced
06	CSV Operations	3 patterns	Beginner → Intermediate
07	Error Handling	4 patterns	Beginner → Intermediate
08	Date/Time	4 patterns	Beginner → Intermediate
09	Advanced Patterns	5 patterns	Advanced
10	Real-World Mappings	6 patterns	Intermediate → Advanced

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01 — Array Manipulation

Pattern	File	Difficulty
Filter by Condition	filter-by-condition.dwl	Beginner
Map Transform	map-transform.dwl	Beginner
Flatten Nested Arrays	flatten-nested.dwl	Intermediate
Group by Field	group-by-field.dwl	Intermediate
Distinct Values	distinct-by.dwl	Intermediate
Order/Sort	order-by.dwl	Beginner
Reduce/Accumulate	reduce-accumulate.dwl	Advanced
Zip Arrays	zip-arrays.dwl	Intermediate

02 — Object Transformation

Pattern	File	Difficulty
Rename Keys	rename-keys.dwl	Beginner
Remove Keys	remove-keys.dwl	Beginner
Merge Objects	merge-objects.dwl	Intermediate
Pluck Values	pluck-values.dwl	Intermediate
Dynamic Keys	dynamic-keys.dwl	Advanced
Nested Object Update	nested-object-update.dwl	Advanced

03 — String Operations

Pattern	File	Difficulty
Split and Join	split-join.dwl	Beginner
Regex Match/Replace	regex-match-replace.dwl	Intermediate
Case Conversion	camel-to-snake.dwl	Intermediate
Template Strings	template-strings.dwl	Beginner
String Padding	string-padding.dwl	Intermediate

04 — Type Coercion

Pattern	File	Difficulty
String to Date	string-to-date.dwl	Intermediate
Number Formatting	number-formatting.dwl	Beginner
Boolean Handling	boolean-handling.dwl	Beginner
Custom Types	custom-types.dwl	Advanced

05 — XML Handling

Pattern	File	Difficulty
XML to JSON	xml-to-json.dwl	Intermediate
JSON to XML	json-to-xml.dwl	Intermediate
Namespace Handling	namespace-handling.dwl	Advanced
CDATA Handling	cdata-handling.dwl	Intermediate
Attribute Extraction	attributes-extraction.dwl	Intermediate

06 — CSV Operations

Pattern	File	Difficulty
CSV to JSON	csv-to-json.dwl	Beginner
JSON to CSV	json-to-csv.dwl	Beginner
Custom Separator	custom-separator.dwl	Intermediate

07 — Error Handling

Pattern	File	Difficulty
Default Values	default-values.dwl	Beginner
Try Pattern	try-pattern.dwl	Intermediate
Error Response Builder	error-response-builder.dwl	Intermediate
Conditional Error	conditional-error.dwl	Intermediate

08 — Date/Time

Pattern	File	Difficulty
Date Formatting	date-formatting.dwl	Beginner
Timezone Conversion	timezone-conversion.dwl	Intermediate
Date Arithmetic	date-arithmetic.dwl	Intermediate
Epoch Conversion	epoch-conversion.dwl	Intermediate

09 — Advanced Patterns

Pattern	File	Difficulty
Recursive Transform	recursive-transform.dwl	Advanced
Custom Functions	custom-functions.dwl	Advanced
Multi-Level GroupBy	multi-level-groupby.dwl	Advanced
Dynamic Schema	dynamic-schema.dwl	Advanced
Tail Recursion	tail-recursion.dwl	Advanced

10 — Real-World Mappings

Pattern	File	Difficulty
Salesforce to SAP	salesforce-to-sap.dwl	Advanced
REST API Flattening	rest-api-flattening.dwl	Intermediate
EDI to JSON	edi-to-json.dwl	Advanced
Batch Payload Split	batch-payload-split.dwl	Intermediate
SOAP to REST	soap-to-rest.dwl	Intermediate
Canonical Data Model	canonical-data-model.dwl	Advanced

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References

• DW 2.x Cheatsheet | PDF download
• Anti-Patterns & Common Mistakes
• DW 1.0 → 2.0 Migration Guide
• Playground Tips

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Anypoint Exchange Modules

Reusable DataWeave utility libraries — import via Maven, no copy-paste needed.

Module	Description	Status
dw-string-utils	15+ string functions (camelize, slugify, mask, etc.)	Live on Exchange
dw-date-utils	11 date functions (addDays, diffDays, toEpoch, etc.)	Live on Exchange
dw-collection-utils	15+ collection functions (chunk, deepMerge, pivot, etc.)	Live on Exchange
dw-error-handler	8 error functions (classifyError, isRetryable, etc.)	Live on Exchange
dw-xml-helpers	10 XML functions (stripNamespaces, xpathLike, etc.)	Live on Exchange

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Contributing

We welcome contributions! See CONTRIBUTING.md for guidelines on adding patterns, submitting PRs, and code style requirements.

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License

MIT — Copyright (c) 2026 Shakar Bisetty

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Built by WeavePilot — curated DataWeave patterns for the MuleSoft community.