mirror of
https://github.com/johndoe6345789/low-code-react-app-b.git
synced 2026-04-24 13:44:54 +00:00
63 lines
1.4 KiB
Markdown
63 lines
1.4 KiB
Markdown
# JSON Expression System
|
|
|
|
This document describes the supported JSON expression patterns used across JSON UI schemas.
|
|
Legacy compute functions have been removed in favor of expression strings and value templates.
|
|
|
|
## Core Concepts
|
|
|
|
### Expressions
|
|
|
|
Expressions are string values that resolve against a data + event context:
|
|
|
|
```json
|
|
{
|
|
"expression": "event.target.value"
|
|
}
|
|
```
|
|
|
|
Supported expression patterns:
|
|
|
|
- `data` or `event`
|
|
- Dot access: `data.user.name`, `event.target.value`
|
|
- Literals: numbers, booleans, `null`, `undefined`, quoted strings
|
|
- Time: `Date.now()`
|
|
- Array filtering:
|
|
- `data.todos.filter(completed === true)`
|
|
- `data.users.filter(status === 'active').length`
|
|
|
|
### Value Templates
|
|
|
|
Value templates are JSON objects whose string values are evaluated as expressions:
|
|
|
|
```json
|
|
{
|
|
"valueTemplate": {
|
|
"id": "Date.now()",
|
|
"text": "data.newTodo",
|
|
"completed": false
|
|
}
|
|
}
|
|
```
|
|
|
|
### Conditions
|
|
|
|
Conditions use expression strings that are evaluated against the data context:
|
|
|
|
```json
|
|
{
|
|
"condition": "data.newTodo.length > 0"
|
|
}
|
|
```
|
|
|
|
Supported condition patterns:
|
|
|
|
- `data.field > 0`
|
|
- `data.field.length > 0`
|
|
- `data.field === 'value'`
|
|
- `data.field != null`
|
|
|
|
## Legacy Compute Functions (Removed)
|
|
|
|
Schemas should no longer reference function names in `compute`, `transform`, or string-based
|
|
condition fields. Use `expression` and `valueTemplate` instead.
|