jatg is a low configuration tool to generate files based on templates.
Most template generation tools require elaborate configurations, lack intuitive usage, are tied to a specific framework or do not support variable transformations. The objective of this tool is to be as intuitive as possible while providing a flexible feature set.
Simply create your template files, add them to the configuration file and then run jatg
to generate the resulting files.
You can create the file by running npx jatg --init
, or just start by copying the example below:
templates.json
{
"$schema": "https://unpkg.com/jatg/templates.schema.json",
"templates": [
{
"name": "my-awesome-template",
"sourcePaths": ["./templates"],
"outputPath": "./src/modules",
"variables": [
{
"variable": "name",
"name": "Module Name"
}
]
}
]
}
Read the configuration reference for a list of all possible properties.
You can have as many files as needed for a single template.
templates/%name%.ts
export class %name.pascalCase% {
// ...
}
The template can have variables, and they can be transformed through functions. Read more about them in the variables reference.
Just run the CLI to generate files based on the templates created.
You'll be prompted which template you want to generate, and what are the variable values.
npx jatg
Pretty straightforward, isn't it?
A template can have multiple variables. Those can be defined in the configuration and can be used to make template contents and file names dynamic.
The syntax is the variable name surrounded by percentages (%variable_name%
) and the value can be formatted through special functions, separated by dots (%variable_name.upper%
).
For the variable named entity
and the value user-post
, here are a few examples:
Template | Result | What is hapenning? |
---|---|---|
%entity% |
user-post |
prints the variable value as-is |
%entity.upper% |
USER-POST |
prints the variable formatted value in uppercase |
%entity.plural.upper% |
USER-POSTS |
prints the variable value formatted in plural and in uppercase |
%entity.plural.dotCase.upper% |
USER.POSTS |
prints the variable value formatted in plural, in dot case and in uppercase |
Variables can be used in template file contents, the template file name and the configuration outputPath
.
Variables that are not defined in the configuration file will be ignored and kept as-is. However, valid variables with invalid formatting functions will throw an error.
These are based on the basic string functions included in JavaScript.
Function | Before | After |
---|---|---|
upper |
"TwoWords" | "TWOWORDS" |
lower |
"TwoWords" | "twowords" |
trim |
" TwoWords " | "TwoWords" |
unaccent |
"maçã" | "maca" |
These functions use change-case under the hood.
Function | Result |
---|---|
camelCase |
twoWords |
capitalCase |
Two Words |
constantCase |
TWO_WORDS |
dotCase |
two.words |
kebabCase |
two-words |
noCase |
two words |
pascalCase |
TwoWords |
pascalSnakeCase |
Two_Words |
pathCase |
two/words |
sentenceCase |
Two words |
snakeCase |
two_words |
trainCase |
Two-Words |
initials |
TW |
These functions use pluralize under the hood.
Function | Result |
---|---|
plural |
twoWords |
singular |
twoWord |
The sourcePaths
is a list of paths to template files and directories that contain template files.
For directories, all files inside it will be considered templates. The directory structure will be kept for the generated results.
The file names don't need to follow any specific extension.
If you need to, you can end them with .template
.
The .template
extension will be removed for the resulting file.
The file names, directories and the outputPath
can contain variables.
Here's an example of the folder structure:
templates/
├── entities/
│ └── %name%.entity.ts.template
└── models/
└── %name%.model.ts.template
The templates.json file:
// templates.json
{
// ...
"sourcePaths": ["./templates"],
"outputPath": "./src/modules/%name%",
// ...
}
The resulting files for the variable name
being "product":
src/
└── modules/
└── product/
├── entities/
│ └── product.entity.ts
└── models/
└── product.model.ts
Template files must be in plain text encoded in UTF-8. The files can contain as many variables as needed.
The format of the template.json
file is also documented through the TemplateConfiguration TypeScript interface and the JSON Schema.
Property | Type | Required | Description |
---|---|---|---|
templates |
array<Template Definition> | Required | The list of templates that can be generated |
composites |
array<Composite Definition> | The list of templates that are a combination of multiple templates |
Property | Type | Required | Description |
---|---|---|---|
name |
string | Required | The template name |
sourcePaths |
array<string> | Required | The path list of template files or directories containing templates |
outputPath |
string | Required | The output directory where the source paths will be copied into. The path can contain variables. |
variables |
array<Variable Definition> | Required | The variables that the user can type. These variables will be replaced in the final template |
Property | Type | Required | Description |
---|---|---|---|
variable |
string | Required | The variable identification |
name |
string | A human-redable name | |
description |
string | A human-redable description | |
type |
"text" | "number" |
The variable type. This is used for input validation. Defaults to "text" . |
|
choices |
array<string> | A list of choices that the user can pick. If this property defined, the user can only pick one of these options. | |
initial |
string | number | The initial value | |
allowEmpty |
boolean | Whether this variable allows empty values. Defaults to false . |
|
preprocessing |
array<string> | The list of formatting functions to apply globally for this variable. |
Property | Type | Required | Description |
---|---|---|---|
name |
string | Required | The name of the composite |
templates |
array<string> | Required | The list of template names that will be combined |
You can run the generation through npx by simply running the command: npx jatg
.
You can also install globally through npm install --global jatg
and run it directly through jatg
.
You can also install it as a dev dependency to your project through npm install -D jatg
and add a script in your package.json
:
{
// ...
"scripts": {
"generate": "jatg"
}
// ...
}
Then you can run it through npm run generate
.
You can also specify options, such as picking a specific template:
npx jatg --template my-awesome-template
Alternatively, you can use environment variables to set the option values.
Description | Option | Environment Variable | Default Value |
---|---|---|---|
Sets the base for other paths | --base-path , -b |
JATG_BASE_PATH |
./ |
The path for the configuration file | --templates-config , -c |
JATG_TEMPLATE_CONFIG_PATH |
./templates.json |
Sets which template will be used, which will not be prompted | --template , -t |
JATG_TEMPLATE_NAME |
|
Sets a template variable value, which will not be prompted | JATG_VARIABLE_* 1 |
||
Whether the generated files should overwrite existing ones | --overwrite , -o |
false | |
Initializes a new template | --init |
||
Prints the command manual | --help |
||
Prints the jatg version | --version |
Footnotes
-
Environment variables prefixed with
JATG_VARIABLE_
will fill the respective template variable. For example, if you want to set the value of a template variable namedfoobar
, you can add the environment variableJATG_VARIABLE_FOOBAR
and it will not be prompted on generation. ↩