String refs (ref="myInput" + this.refs.myInput) were deprecated in React 16.3, warn in React 18.3.1, and are removed in React 19.
Quick Pattern Map
| Pattern | Reference |
|---|---|
| Single ref on a DOM element | → patterns.md#single-ref |
| Multiple refs in one component | → patterns.md#multiple-refs |
| Refs in a list / dynamic refs | → patterns.md#list-refs |
| Callback refs (alternative approach) | → patterns.md#callback-refs |
| Ref passed to a child component | → patterns.md#forwarded-refs |
Scan Command
# Find all string ref assignments in JSX
grep -rn 'ref="' src/ --include="*.js" --include="*.jsx" | grep -v "\.test\."
grep -rn "this.refs." src/ --include=".js" --include=".jsx" | grep -v ".test."
Both should be migrated together - find the `ref="name"` and the `this.refs.name` accesses for each component as a pair.
## The Migration Rule
Every string ref migrates to `React.createRef()`:
1. Add `refName = React.createRef();` as a class field (or in constructor)
2. Replace `ref="refName"` → `ref={this.refName}` in JSX
3. Replace `this.refs.refName` → `this.refName.current` everywhere
Read `references/patterns.md` for the full before/after for each case.