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https://github.com/nishants/jeyson
A JSON template system.
https://github.com/nishants/jeyson
inbuilt-directives javascript json json-template npm template-engine template-language
Last synced: 8 days ago
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A JSON template system.
- Host: GitHub
- URL: https://github.com/nishants/jeyson
- Owner: nishants
- Created: 2016-05-31T04:36:41.000Z (over 8 years ago)
- Default Branch: master
- Last Pushed: 2018-12-08T08:46:53.000Z (almost 6 years ago)
- Last Synced: 2024-04-28T12:43:26.232Z (7 months ago)
- Topics: inbuilt-directives, javascript, json, json-template, npm, template-engine, template-language
- Language: JavaScript
- Size: 79.1 KB
- Stars: 8
- Watchers: 2
- Forks: 2
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
Awesome Lists containing this project
README
## Jeyson Templates
- Every json is a valid template in itself.
- The templates can have expressions, which can execute javascript.
- These templates are compiled in context of a scope.
- Directives can pass instructions to compiler.
- Inbuilt directives for iterating, conditional contents, including other templates etc.
- Custom directives can replace/modify template body, execute expressions, read other templates.
### Compiling Templates
```javascript
var jeyson = require('jeyson').create(),
scope = {message: 'Hello!'},
templateJson = {"message": "{{message}}"},
compiled = jeyson.compile(scope, templateJson);
```
### Expressions
An expression is defined as '__{{expr}}__'
Following __template.json__ :
```javascript
{
"age": "{{21 + 33}}"
}
```
is compiled to
```javascript
{
"age": 54
}
```
### Javascript in Expressions.
Any valid javascript snippet is a valid expression, e.g following __template.json__ :
```javascript
{
"list" : "{{'one,two,three,four,five'.split(',')}}",
}
```
is compiled to
```javascript
{
"list" : ["one", "two", "three", "four", "five"],
}
```
### Scopes
Any field on scope object, is available as local variable in expressions.
e.g. Given scope defined as :
```javascript
var scope = {message: "Hello !"},
```
then following __template.json__ :
```javascript
{
"message": "{{message}}"
}
```
is compiled to
```javascript
{
"message": "Hello !"
}
```
#### Scope can have methods
e.g. Given scope defined as :
```javascript
var scope = {
message: function(){
return "Hello !";
}
};
```
then following __template.json__ :
```javascript
{
"message": "{{message()}}"
}
```
is compiled to
```javascript
{
"message": "Hello !"
}
```
### Directives
- Directive is a field with name starting with __"@"__
- Directive __body__ is the parent subtree of directive field
- Directive argument is the value of directive field.
E.g.
```javascript
{
"list" : {
"@repeat" : "name in ['one','two','three','four','five']",
"id" : "{{$index + 1}}",
"name" : "{{name}}",
}
}
```
- __"list"__ value is directive body (has a directive child)
- __@repeat__ is directive name
- __count in [1,2,3,4,5]__ is directive argument
It will compile to following json :
```javascript
{
"list": [ {"id": "1","name" : "one"},
{"id": "2","name" : "two"},
{"id": "3","name" : "three"},
{"id": "4","name" : "four"},
{"id": "5","name" : "five"}];
}
```
# Conditional Blocks & System Directives
Following are the conditional directives
1. switch
2. if
3. ignore-if (a system directive)
### @switch
#### Will replace the body with "@[value]", "@default" or null based on choice.
```javascript
scope = {role : {name: "admin"}}
template = {
"user" : {
"role" : {
"@switch" : "role.name",
"@admin" : {"name" : "admin"},
"@visitor" : {"name" : "visitor"},
"@default" : {"name" : "guest"}
}
}
```
Will compile to
```javascript
template = {
"user" : {
"role" : {"name" : "admin"}
}
```
### @if, @then, @else
#### Will set field value to null, "@then" or "@else", by condition
```javascript
{
"author" : "ABC",
"book" : {
"@if" : "1 == 2",
"@then" : {"title" : "Harry Potter"}
"@else" : "unknown",
}
}
```
will result in
```javascript
{
"author" : "ABC",
"book" : "unknown"
}
```
```javascript
{
"author" : "ABC",
"book" : {
"@if" : "1 == 1",
"@then" : {"title" : "Harry Potter"}
}
```
will result in
```javascript
{
"author" : "ABC",
"book" : {"title" : "Harry Potter"}
}
```
```javascript
{
"author" : "ABC",
"book" : {
"@if" : "1 == 2",
"@then" : {"title" : "Harry Potter"}
}
```
will result in
```javascript
{
"author" : "ABC",
"book" : null
}
```
### @ignore-if
#### Will not render the field itself, if the condition is false.
e.g
```javascript
{
"author" : "ABC",
"book" : {
"@ignore-if": "1 == 1",
"title" : "Harry Potter"
}
}
```
will result in
```javascript
{
"author" : "ABC"
}
```
### Inbuilt Directives
Inbuilt directives for repeating, including other json etc.
### @repeat
- $index
- array
- result
### Custom Directives
- Reading scope
- Executing expressions
- Modifying body
- Replacing body
- Reading other templates by relative path
### Source code of inbuilt directives