Handle YAML parse errors in js-yaml

YAML written by people often contains mistakes, so code that loads it should catch errors and report them clearly.

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Handle YAML parse errors in js-yaml: screenshot of the example below running — The code below, running in Chromium on our server (Oct 12, 2026). Press Run to see it live and change it.

How it works

Wrap load in try/catch. The README calls load inside a try block with a catch for errors. The example puts that pattern in a small safeLoad helper. [1]
Compare inputs. The helper runs on several snippets: valid ones print their data, broken ones print the first line of the error message instead of stopping the script. [1]

Run and edit it

It runs in your browser, in a sandboxed frame that cannot see this site; the packages load from esm.sh only after you press Run.

import { load } from 'js-yaml'

function safeLoad(label, text) {
  try {
    const document = load(text)
    console.log('OK   ' + label + ' -> ' + JSON.stringify(document))
  } catch (e) {
    console.log('FAIL ' + label + ' -> ' + e.message.split('\n')[0])
  }
}

safeLoad('simple map', 'greeting: hello')
safeLoad('list', '- a\n- b\n- c')
safeLoad('unclosed list', 'items: [1, 2, 3')
safeLoad('bad indent', 'server:\n  host: a\n port: 80')
safeLoad('duplicate key', 'name: a\nname: b')
safeLoad('unclosed quote', 'title: "hello')
safeLoad('nested', 'user:\n  name: Ada\n  tags: [x, y]')

Ctrl/⌘ + Enter runs

Fix one of the broken snippets and watch it move from the error list to the OK list. Code written by AgentGid [1].

Checked Oct 12, 2026: it starts without errors in Chromium with js-yaml 5.4.3. Needs WebGL.

More js-yaml examples

Parse YAML with js-yaml load() Write YAML with js-yaml dump() Update a YAML config with js-yaml

Sources

js-yaml README (GitHub)

Explanations written by AgentGid from the official docs; the numbers in brackets point here. The code marked "written by AgentGid" is ours and free to copy.

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