DOM Notation JS
Project description
dnjs
dnjs is a pure subset of JavaScript that wants to replace (across many host languages):
- overly limiting/baroque configuration languages
- mucky string based
html/xmltemplating
It is powerful yet familiar, and the reduced syntax makes it easy to implement (the reference implementation in Python took a couple of days to write) and easy to reason about. Currently the state is very alpha - see the TODO at the end.
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║ ║ ║ JSON ║ dnjs ║ JavaScript ║
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Installing the reference interpreter
pip install dnjs
dnjs --help
Examples
Some of these examples reference other files in the examples folder.
For configuration:
import { environments } from "./global.dn.js"
// names of the services to deploy
const serviceNames = ["signup", "account"]
const makeService = (environment, serviceName) => ({
name: serviceName,
ip: environment === environments.PROD ? "189.34.0.4" : "127.0.0.1"
})
export default (environment) => serviceNames.map(
(v, i) => makeService(environment, v)
)
Let's use the reference implementation written in Python to run these (this also has a Python API documented below):
dnjs examples/configuration.dn.js examples/environment.json | jq
Gives us:
[
{
"name": "signup",
"ip": "127.0.0.1"
},
{
"name": "account",
"ip": "127.0.0.1"
}
]
For html templating
dnjs prescribes functions for making html, that handily are a subset of mithril (this makes it possible to write powerful, reusable cross-language html components).
Given the file commentsPage.dn.js:
import m from "mithril"
import { page } from "./basePage.dn.js"
const commentList = (comments) => m("ul",
comments.map((comment, i) => m("li", `Comment ${i} says: ${comment.text}`))
)
export default (comments) => page(commentList(comments))
Then in a python webserver we can render the file as html:
from dnjs import render
@app.route("/some-route"):
def some_route():
...
return render("commentsPage.dn.js", comments)
And the endpoint will return:
<html>
<head>
<script src="someScript.js">
</script>
</head>
<body>
<ul>
<li>
Comment 0 says: hiya!
</li>
<li>
Comment 1 says: oioi
</li>
</ul>
</body>
</html>
Or we can use the same components on the frontend with mithril:
import page from "../commentsPage.dn.js"
...
m.mount(document.body, page)
Or we can render the html on the command line similar to before:
dnjs examples/commentsPage.dn.js examples/comments.json --html
Note, that without the --html flag, we still make the following JSON, the conversion to html is a post-processing stage:
{
"tag": "html",
"attrs": {
"className": ""
},
"children": [
{
"tag": "head",
"attrs": {
...
For css templating
Using --css will post-process eg:
export default {
".bold": {"font-weight": "bold"},
".red": {"color": "red"},
}
to:
.bold {
font-weight: bold;
}
.red {
color: red;
}
As a jq replacement
JSON='[{foo: 1, bar: "one"}, {foo: 2, bar: "two"}]'
echo $JSON | dnjs - -p 'a=>a.map(b=>[b.bar, b.foo])'
[["one", 1], ["two", 2]]
csv
echo $JSON | dnjs - -p 'a=>a.map(b=>[b.bar, b.foo])' --csv
"one",1
"two",2
csv, raw
echo $JSON | dnjs - -p 'a=>a.map(b=>[b.bar, b.foo])' --csv --raw
one,1
two,2
jsonl
(While dnjs is implemented in python, this is very slow).
JSON='{foo: 1, bar: "one"}\n{foo: 2, bar: "two"}'
echo $JSON | while read l; do echo $l | dnjs - -p 'a=>a.bar' --raw; done
one
two
Flattening
Remember, you can flatten arrays with:
.reduce((a, b)=>[...a, ...b], [])
How exactly does dnjs extend JSON?
Remember dnjs is a restriction of JavaScript, the aim is not to implement all of it, any more than JSON is.
Here are all the extensions to JSON:
- Comments with
//. - Optional trailing commas.
- Unquoted keys in objects.
import { c } from "./b.dn.js",import b from "./b.dn.js". Non-local imports are simply ignored (so as to allow importingmas anything).export default a,export const b = c.dicts andlists can be splatted with rest syntax:{...a}/[...a].- Functions can be defined with
const f = (a, b) => csyntax. Brackets are not required for one argument, functions are called with the number of arguments provided. - Ternary expressions, only in the form
a === b ? c : d. Equality should be implemented howeverJavaScriptdoes. - Map, filter, reduce, map over dict, dict from entries, in the form
a.map((v, i) => b),a.filter((v, i) => b),a.reduce((x, y) => [...x, ...y], []),Object.entries(a).map(([k, v], i) => b),Object.fromEntries(a). - Hyperscript, somewhat compatible with mithril -
m("sometag#some-id.some-class.other-class", {"href": "foo.js", "class": ["another-class"]}, children), this evaluates todicts like{"tag": "sometag", "attrs": {"id": "some-id", className: "some-class other-class another-class", "href": "foo.js", "children": children}.m.trust(a)to not escape html. - Multiline templates in the form
`foo ${a}`,dedent(`foo ${a}`).dedentshould work the same as this npm package. - Lists have
.length,.includes(a)attributes.
Name
Originally the name stood for DOM Notation JavaScript.
Python
API
These functions return JSON-able data:
from dnjs import get_default_export, get_named_export
get_default_export(path)
get_named_export(path, name)
This function returns html as a str:
from dnjs import render
render(path, *values)
The types used throughout dnjs are fairly simple dataclasss , there's not much funny stuff going on in the code - check it out!
Development
Install dev requirements with:
pip install -r requirements-dev.txt
Run tests with:
pytest
Pin requirements with:
pip-compile -q; cat requirements.in requirements-dev.in | pip-compile -q --output-file=requirements-dev.txt -
Rebuild and publish (after upversioning) with:
# up version setup.py
rm dist/*; python setup.py sdist bdist_wheel; twine upload dist/*
JS
Javascript validation library to follow - see TODO section below.
Run tests with:
npm install
npm test
TODO
- Use on something real to iron out bugs.
- Spec out weird behaviour + make the same as js:
- numbers
===
- Nicer docs:
- Write up why we don't need filters like | to_human.
- Consider
onclick,onkeydown,on...functions... and how we want to handle them / attach them on reaching the browser in a isomophic setup. - Decide what else should be added:
- Common string functions like upper case, replace etc?
parseIntetc..
- Standalone (in
c/rust/go? withPythonbindings) to JSON program. - Write JS library that simply wraps mithril render and has a
dnjs.isValid(path)function that uses the grammar (doing this may involve removing somelark-specific bits in the grammar. - Typescript support?
- Consider what prevents
dnjsfrom becoming a data interchange format - eg. infinite recursion.--safemode? Specify PATHs that it's permitted to import from. - Allow importing JSON using Experimental JSON modules](https://nodejs.org/api/esm.html#esm_experimental_json_modules).
- Remove accidental non-js compatability - eg. template grammar is a bit wacky.
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