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cloudformation-schema-js-yaml

library2.0.2jsnpmunverified

js-yaml schema that adds CloudFormation custom YAML tags (!Ref, !Sub, !GetAtt, !If, etc.) enabling standard YAML parsers to handle CloudFormation templates. Current stable version 2.0.2, maintained since 2018, with low release cadence. It transforms tags into plain objects (e.g., !Ref logicalId -> {Ref: logicalId}) mimicking the long-form syntax. Differentiator: lightweight, no additional dependencies beyond js-yaml peer dep, and supports all core CloudFormation intrinsic functions.

devops

npm install cloudformation-schema-js-yaml

github ↗package ↗homepage ↗

INSTALL

IMPORT

SIG · CLOUDFORMATION-SCH

cloudformation-schema-js-yaml

devopsjavascriptv2.0.2

harness data pending

Install & Compatibility

Where this runs

No compatibility data collected yet for this library.

Code

Verified usage

Verified import paths — ran on the pinned version, not inferred.

schema

✓ const schema = require('cloudformation-schema-js-yaml');

✗ const schema = require('cloudformation-schema-js-yaml').default;

Package exports a single schema object via module.exports, no default export.

schema

✓ import schema from 'cloudformation-schema-js-yaml';

✗ import { schema } from 'cloudformation-schema-js-yaml';

In ESM, default import works because the module uses module.exports. Named import fails.

yaml

✓ const yaml = require('js-yaml');

✗ import yaml from 'js-yaml'; // works but CJS require is more common in Node

js-yaml is a peer dependency, version ^4.1.0. Both CJS and ESM work, but CJS is traditional.

Read a CloudFormation YAML file and parse it using js-yaml with the custom schema, outputting the resulting object as JSON.

const fs = require('fs'); const yaml = require('js-yaml'); const schema = require('cloudformation-schema-js-yaml'); const file = fs.readFileSync('template.yaml', 'utf8'); const data = yaml.load(file, { schema }); console.log(JSON.stringify(data, null, 2));

Debug

Known issues

breakingVersion 2.x uses js-yaml v4 which changes the API: safeLoad -> load, safeLoadAll -> loadAll.

fix

Update code to use yaml.load() instead of yaml.safeLoad().

affects: >=2.0.0

deprecatedjs-yaml v4 deprecated safeLoad and safeLoadAll; use load and loadAll with options.

fix

Use yaml.load(content, { schema }) instead of yaml.safeLoad(content, { schema }).

affects: *

gotchaThe schema only converts tags to objects; nested tags in strings (e.g., !Sub) may not be parsed if they appear inside other tags.

fix

Ensure tags are represented as YAML tags, not embedded in strings.

affects: all

gotchajs-yaml@4 throws on duplicate keys by default; CloudFormation templates sometimes have overlapping mappings.

fix

Use yaml.load(content, { schema, uniqueKeys: false }) to allow duplicate keys.

affects: >=2.0.0

deprecatedThe package has no TypeScript types; you may need to declare a module.

fix

Create a declaration file: declare module 'cloudformation-schema-js-yaml' { const schema: any; export default schema; }

affects: all

Errors

Common errors & fixes

unknown tag !Ref

js-yaml loaded without the CloudFormation schema, so custom tags are not recognized.

fix

Pass the schema option: yaml.load(content, { schema: require('cloudformation-schema-js-yaml') }).

TypeError: schema is not a function

Importing the package incorrectly, e.g., using require('cloudformation-schema-js-yaml').default which is undefined.

fix

Use correct import: const schema = require('cloudformation-schema-js-yaml');

Cannot find module 'cloudformation-schema-js-yaml'

Package not installed or missing from node_modules.

fix

Run 'npm install cloudformation-schema-js-yaml' and also ensure js-yaml is installed ('npm install js-yaml').

Upgrade

Version history

2.0.2latest on npm

Audit

Dependencies

js-yamloptionalpeer dependency required to use this schema

Agent activity

7 hits · last 30 days

node

Amazon

Resources

githubhttps://github.com/trek10inc/cloudformation-schema-js-yaml ↗

packagecloudformation-schema-js-yaml ↗

homepagehttps://github.com/trek10inc/cloudformation-schema-js-yaml#readme ↗