@bam.tech/kettle
v2.1.1
Published
The templating engine tailored for boilerplates
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Kettle
The templating engine tailored for boilerplates
Design philosophy
As templating engines were historically tailored for the needs of server side rendering they allow for powerful integration of conditions, loops, replacements, includes, ... but don't care about breaking syntax.
The consequence is that when using those engines for boilerplate templating it breaks the code and prevents you from using tools such as linting, typings and unit tests live while templating. Thus, making the development cycle of a boilerplate tedious.
Kettle aims to bring the power of templating without breaking any syntax by focusing only on basic tools and leveraging comments available in (almost) any programing language.
Usage
Install Kettle
yarn add @bam.tech/kettle
npm install @bam.tech/kettle
Running Kettle
It is recommended to use Kettle using Gulp
const { src, dest } = require('gulp');
const { transformFactory } = require('kettle');
src(['path/to/template'])
.pipe(
transformFactory({
values: {
isTrue: true,
isFalse: false,
appName: 'myApp',
functionName: 'myFunction',
},
})
)
.pipe(dest('path/to/output'));
Using Kettle templates in paths
Kettle replaces values in paths:
- Input:
path/to/__replace__appName__/file.env
will outputpath/to/myApp/file.env
To add a folder/file conditionnaly:
With
path/to/__replace__appName____if__isTrue__/subFolder__if__isTrue__/file.env
, the resulting file will appear in the written file at the pathpath/to/myApp/subFolder/file.env
With
path/to/__replace__appName__/subFolder__if__isFalse__/file.env
, Kettle will not write any fileWith a
// __include_if_isTrue_
comment, the file will be included and the comment line removedWith a
// __include_if_isFalse_
comment, the file will not be included in the output at allYou can also chain conditions with multiple include lines. The position of the comment in the file does not matter
// __include_if_isTrue_
// __include_if_isFalse_
const thisFileWillNotBeRendered = true;
Reverse assertions
It is possible to reverse assertions using !
For example, path/to/__replace__appName__/subFolder__if__!isFalse__/file.env
will render path/to/myApp/subFolder/file.env
Using Kettle templates in files
In files content, Kettle will turn this:
const import1 = require('path/to/imports1__if__isFalse__/import1.js');
const import2 = require('path/to/imports2__if__isTrue__/import2.js');
const import2 = require('path/to/imports2__if__!isTrue__/import2.js');
// __if__isTrue__
__replace__functionName__();
console.log('__replace__appName__');
// __endif__
// __if__isFalse__
shouldNotAppear();
// __endif__
// __if__!isTrue__
shouldNotAppear();
// __endif__
into
const import2 = require('path/to/imports1/import1.js');
myFunction();
console.log('myApp');
Supported comment syntax:
//
#
- Please open an issue if you find a comment syntax which doesn't work with Kettle
Search and replace
Sometimes it is impossible to use characters such as "_" in strings. To allow for some edge cases, a search and replace tool has been included. It is recommended to avoid using this method.
transformFactory({
replaceList: [
{
from: 'foo',
to: 'hello',
},
{
from: 'Bar',
to: 'World',
},
],
});
This will transform all occurences of foo
and Bar
. fooBar
will become helloWorld
Custom replacement blocks
It is possible to customize the __replace__<myVar>__
, __if__<myVar>__
and __endif__
blocks.
Examples are provided in kettle.replace.test.ts
Syntax highlighting
VSCode
To highlight Kettle syntax it is advised to install the VSCode Highlight plugin and use the following rules in .vscode/settings.json
:
{
"highlight.regexes": {
"(.*?__if__)(!.+?)(__.*?)\\n": [
{
"backgroundColor": "#a06f5f",
"color": "#FFF"
},
{
"backgroundColor": "#a06f5f",
"color": "#ffbfb4",
"fontWeight": "bold"
},
{
"backgroundColor": "#a06f5f",
"color": "#FFF"
}
],
"(.*?__if__)([^!]+?)(__.*?)\\n": [
{
"backgroundColor": "#a06f5f",
"color": "#FFF"
},
{
"backgroundColor": "#a06f5f",
"color": "#c7ffa4",
"fontWeight": "bold"
},
{
"backgroundColor": "#a06f5f",
"color": "#FFF"
}
],
"((?:\\/\\/|#) __if__)([^!]+?)(__)": [
{
"backgroundColor": "#808080",
"color": "#FFF"
},
{
"backgroundColor": "#808080",
"color": "#c7ffa4",
"fontWeight": "bold"
},
{
"backgroundColor": "#808080",
"color": "#FFF"
}
],
"((?:\\/\\/|#) __if__)(!.+?)(__)": [
{
"backgroundColor": "#808080",
"color": "#FFF"
},
{
"backgroundColor": "#808080",
"color": "#ffbfb4",
"fontWeight": "bold"
},
{
"backgroundColor": "#808080",
"color": "#FFF"
}
],
"((?:\\/\\/|#) __endif__)": [
{
"backgroundColor": "#808080",
"color": "#FFF"
}
],
"(__replace__)(.+?)(__)": [
{
"backgroundColor": "#5F9EA0",
"color": "#FFF"
},
{
"backgroundColor": "#5F9EA0",
"color": "#FFF",
"fontWeight": "bold"
},
{
"backgroundColor": "#5F9EA0",
"color": "#FFF"
}
]
}
}