Stream related functions: Html minifier, Markdown parser, concat as stream and streamify a string function.
stream-sac
Stream related functions: Html minifier, Markdown parser, concat as stream and streamify a string function.
Installation
Usage
HtmlMinifier.js
Minify Html with a transform stream. Line breaks and spaces are combined into 1 space.
The input should be valid. Optional pass jsMinifier and cssMinifier to minify inline.
import fs from "node:fs";
import { pipeline } from "node:stream";
import {
HtmlMinifier,
} from "stream-sac/source/html/HtmlMinifier.js";
const source = `./tests/manual/html.html`;
const destination = `./tests/output/html.min.html`;
const htmlMinifier = new HtmlMinifier({
jsMinifier: (x) => x, // sync function
cssMinifier: (y) => y,
});
htmlMinifier.setEncoding(`utf8`);
pipeline(
fs.createReadStream(source),
htmlMinifier,
fs.createWriteStream(destination),
(error) => {
if (error) {
console.error(error);
}
});
MarkdownParser.js
Parse markdown into html with a transform stream. The input should be valid. Check the demo in the demo/ folder. Deployed demo at stream-sac.vercel.app/editor
import {
MarkdownParser,
} from "stream-sac/source/markdown/MarkdownParserNode.js";
const markdownStream = new MarkdownParser({
// all optional
languagePrefix: `language-`,
highlight: function (str, lang) {
// import hljs to get code highlighting
if (lang && hljs.getLanguage(lang)) {
try {
return hljs.highlight(lang, str).value;
} catch (__) {}
}
return ``;
},
// for example to resize images on the fly
mediaHook: function (src, alt) {
return `<img alt="${alt}" src="${src}">`;
},
// for example to disable all external links
linkHrefHook: function (src) {
if (!src.startsWith("https://example.com")) {
return "#";
}
return src;
}
});
Deno and Web
createMarkdownParserStream takes the same options as above, however it is a function that returns a web transform stream. It expects data to be strings, so TextDecoderStream may have to be used.
import { createMarkdownParserStream } from "stream-sac/built/MarkdownParserWeb.es.js"
// or
import { createMarkdownParserStream } from "https://unpkg.com/stream-sac/built/MarkdownParserWeb.es.js";
streamifyStringFunction.js
Take any function that takes as input and out a string, and return a transform stream creator, that does the same on streams.
import {
streamifyStringFunction,
} from "stream-sac/source/streamifyStringFunction.js";
// Caesar cipher -only lowercase letters
const shift = 1;
const lowera = 97
const lowerZ = 122;
const range = lowerZ - lowera + 1;
const encodeCaesar = s => {
return Array.from(s).map(c => {
const unicodeNumber = c.charCodeAt(0);
if (unicodeNumber >= lowera && unicodeNumber <= lowerZ) {
return String.fromCharCode(((unicodeNumber - lowera + shift) % range) + lowera);
}
return c;
}).join(``);
};
// transforms a function that works with strings into a function that returns a transform stream
const createCesarEncodeStream = streamifyStringFunction(encodeCaesar);
const cesarEncodeStream = createCesarEncodeStream();
cesarEncodeStream.pipe(process.stdout);
cesarEncodeStream.write(`The lazy fox ...`);
cesarEncodeStream.write(`jumps over !`);
cesarEncodeStream.end(); // output: Tif mbaz gpy ...kvnqt pwfs !
concatAsStream.js
Concatenate arrays, strings, streams, promises as one Readable stream.
import {
concatAsStream,
} from "stream-sac/source/concatAsStream.js";
import { pipeline } from "node:stream";
import fs from "node:fs";
import { concatAsStream } from "../../source/concatAsStream.js";
// example sources
const readStream = fs.createReadStream(`./readme.md`);
const readStreamInPromise = fs.createReadStream(`./changelog.md`);
const promise = Promise.resolve(readStreamInPromise);
const aString = `Hello love
`;
const otherString = `THE END`;
// create
const concatedStream = concatAsStream([
readStream, // stream readme
aString, // String and linebreak
promise, // promise of a stream (changelog)
otherString, // String and linebreak
]);
concatedStream.setEncoding(`utf8`);
// output to standard out, could also output to http response, file, etc.
pipeline(concatedStream, process.stdout, (error) => {
if (error) {
console.error(error);
}
});
