Using Observable for software engineering, programming language and user interface research.
Published
Edited
Sep 11, 2022
Importers
2 stars
createElement([
"div",
{
style: {
padding: "1.25em",
fontFamily: "sans-serif",
borderRadius: "4px",
backgroundColor: "rgb(251, 248, 226)",
border: "1px solid #E0E0E0"
}
},
"This is an example of how to define ",
["a", { href: "https://reactjs.org/docs/introducing-jsx.html" }, "JSX-like"],
" structures directly in JavaScript",
["ol", ["li", "Get bread"], ["li", "Get wine"], ["li", "Get cheese"]]
])
html.div(
{
style: {
padding: "1.25em",
fontFamily: "sans-serif",
borderRadius: "4px",
backgroundColor: "rgb(251, 248, 226)",
border: "1px solid #E0E0E0"
}
},
"This is an example of how to define ",
html.a({ href: "https://reactjs.org/docs/introducing-jsx.html" }, "JSX-like"),
" structures directly in JavaScript",
html.ol(html.li("Get bread"), html.li("Get wine"), html.li("Get cheese"))
)
createElement = {
const createElement = (value, handler = undefined) => {
if (value instanceof Array) {
const attrs =
value[1] instanceof Object &&
!(value[1] instanceof Array || value[1] instanceof Node)
? value[1]
: null;
const content = attrs === null ? value.slice(1) : value.slice(1);
if (value[0] === "#") {
return document.createComment(
value
.slice(1)
.map((_) => `${1}`)
.join()
);
} else {
const node =
value[0] === ""
? document.createDocumentFragment()
: document.createElement(value[0], handler);
attrs &&
Object.entries(attrs).forEach(([k, v]) =>
setElementAttribute(node, k, v)
);
content.forEach((_) =>
appendElementChild(node, createElement(_), handler)
);
return node;
}
} else if (typeof value === "string") {
return document.createTextNode(value);
} else if (typeof value === "number") {
return document.createTextNode(`${value}`);
} else if (typeof value === undefined || typeof value == null) {
return document.createTextNode("");
} else if (value instanceof Node) {
return value;
} else if (handler) {
return handler(value);
}
};
return createElement;
}
appendElementChild = {
const appendElementChild = (node, child, handler) => {
if (child === null || child === undefined) {
return node;
} else if (child instanceof Array) {
child.forEach((_) => appendElementChild(node, _, handler));
} else if (child instanceof Node) {
node.appendChild(child);
} else if (handler) {
return handler(child);
}
return node;
};
return appendElementChild;
}
setElementAttribute = (node, name, value, append = 0, ns = undefined) => {
const t = typeof value;
if (!ns && name.startsWith("on")) {
const n = name.toLowerCase();
if (node[n] !== undefined) {
// We have a callback
node[n] = value;
}
return node;
}
if (!ns & (name === "style") && t === "object") {
// We manage style properties by valle
if (!append) {
node.setAttribute("style", "");
}
Object.assign(node.style, value);
} else if (!ns && name === "value" && node.value !== undefined) {
node.value = value ? value : "";
} else if (!ns && name.startsWith("on") && node[name] !== undefined) {
// We have a callback
node[name] = value;
} else if (value === undefined || value === null) {
// We remove the attribute
ns ? node.removeAttributeNS(ns, name) : node.removeAttribute(name);
} else {
// We have a regular value that we stringify
const v =
t === "number"
? `${value}`
: t === "string"
? value
: JSON.stringify(value);
// If we append, we create an inermediate value.
if (append) {
const e = ns ? node.getAttributeNS(ns, name) : node.getAttribute(name);
const w = `${append < 0 && e ? e + " " : ""}${v}${
append > 0 && e ? " " + e : ""
}`;
ns ? node.setAttributeNS(ns, name, w) : node.setAttribute(name, w);
} else {
ns ? node.setAttributeNS(ns, name, v) : node.setAttribute(name, v);
}
}
return node;
}
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