From 5df222edeac4f2ed6aeccd2752da0b1037170e9e Mon Sep 17 00:00:00 2001
From: Atul Varma <varmaa@gmail.com>
Date: Sat, 6 Feb 2021 07:50:51 -0500
Subject: [PATCH] Process multiple children of <svg>, store SVG as struct.

---
 lib/browser-main.tsx |  46 ++++++++++++++----
 lib/vocabulary.ts    | 111 +++++++++++++++++++++++++++++++++++--------
 2 files changed, 128 insertions(+), 29 deletions(-)

diff --git a/lib/browser-main.tsx b/lib/browser-main.tsx
index 3120fea..616d0d4 100644
--- a/lib/browser-main.tsx
+++ b/lib/browser-main.tsx
@@ -2,40 +2,67 @@ import React, { useState } from "react";
 import ReactDOM from "react-dom";
 
 import _SvgVocabulary from "./svg-vocabulary.json";
-import type { SvgSymbolData } from "./vocabulary";
+import type { SvgSymbolData, SvgSymbolElement } from "./vocabulary";
 
 const APP_ID = "app";
 
 const appEl = document.getElementById(APP_ID);
 
-const SvgVocabulary: SvgSymbolData[] = _SvgVocabulary;
+const SvgVocabulary: SvgSymbolData[] = _SvgVocabulary as any;
 
 if (!appEl) {
   throw new Error(`Unable to find #${APP_ID}!`);
 }
 
-type SvgSymbolProps = {
-  data: SvgSymbolData;
-  scale?: number;
+type SvgSymbolContext = {
   stroke: string;
   fill: string;
 };
 
+type SvgSymbolProps = {
+  data: SvgSymbolData;
+  scale?: number;
+} & SvgSymbolContext;
+
 const px = (value: number) => `${value}px`;
 
+function reactifySvgSymbolElement(
+  ctx: SvgSymbolContext,
+  el: SvgSymbolElement,
+  key: number
+): JSX.Element {
+  let { fill, stroke } = el.props;
+  if (fill && fill !== "none") {
+    fill = ctx.fill;
+  }
+  if (stroke && stroke !== "none") {
+    stroke = ctx.stroke;
+  }
+  return React.createElement(
+    el.tagName,
+    {
+      ...el.props,
+      id: undefined,
+      fill,
+      stroke,
+      key,
+    },
+    el.children.map(reactifySvgSymbolElement.bind(null, ctx))
+  );
+}
+
 const SvgSymbol: React.FC<SvgSymbolProps> = (props) => {
   const d = props.data;
   const scale = props.scale || 1;
 
   return (
     <svg
-      stroke={props.stroke}
-      fill={props.fill}
       viewBox={`0 0 ${d.width} ${d.height}`}
       width={px(d.width * scale)}
       height={px(d.height * scale)}
-      dangerouslySetInnerHTML={{ __html: d.svg }}
-    ></svg>
+    >
+      {props.data.layers.map(reactifySvgSymbolElement.bind(null, props))}
+    </svg>
   );
 };
 
@@ -64,6 +91,7 @@ const App: React.FC<{}> = () => {
       </p>
       {SvgVocabulary.map((symbolData) => (
         <div
+          key={symbolData.name}
           style={{
             display: "inline-block",
             border: "1px solid black",
diff --git a/lib/vocabulary.ts b/lib/vocabulary.ts
index 1b655e4..b8ef486 100644
--- a/lib/vocabulary.ts
+++ b/lib/vocabulary.ts
@@ -1,30 +1,103 @@
 import fs from "fs";
 import path from "path";
 import cheerio from "cheerio";
+import { SVGProps } from "react";
 
 export type SvgSymbolData = {
   name: string;
   width: number;
   height: number;
-  svg: string;
+  layers: SvgSymbolElement[];
 };
 
+export type SvgSymbolElement = (
+  | {
+      tagName: "g";
+      props: SVGProps<SVGGElement>;
+    }
+  | {
+      tagName: "path";
+      props: SVGProps<SVGPathElement>;
+    }
+) & {
+  children: SvgSymbolElement[];
+};
+
+const SUPPORTED_SVG_TAG_ARRAY: SvgSymbolElement["tagName"][] = ["g", "path"];
+const SUPPORTED_SVG_TAGS = new Set(SUPPORTED_SVG_TAG_ARRAY);
+
 const MY_DIR = __dirname;
 const SVG_DIR = path.join(MY_DIR, "..", "svg");
 const VOCAB_PATH = path.join(MY_DIR, "svg-vocabulary.json");
 const SVG_EXT = ".svg";
 
-function removeAttrIfNotNone(
-  attr: string,
-  $: cheerio.Root,
-  g: cheerio.Cheerio
-) {
-  const items = g.find(`[${attr}]`);
-  items.each(function (this: any, i, el) {
-    if ($(this).attr(attr) !== "none") {
-      $(this).removeAttr(attr);
+function onlyTags(
+  elements: cheerio.Element[] | cheerio.Cheerio
+): cheerio.TagElement[] {
+  const result: cheerio.TagElement[] = [];
+
+  for (let i = 0; i < elements.length; i++) {
+    const el = elements[i];
+    if (el.type === "tag") {
+      result.push(el);
     }
-  });
+  }
+
+  return result;
+}
+
+function isSupportedSvgTag(
+  tagName: string
+): tagName is SvgSymbolElement["tagName"] {
+  return SUPPORTED_SVG_TAGS.has(tagName as any);
+}
+
+const SVG_ATTRIB_TO_PROP_MAP: {
+  [key: string]: keyof SvgSymbolElement["props"] | undefined;
+} = {
+  id: "id",
+  fill: "fill",
+  stroke: "stroke",
+  d: "d",
+  "stroke-linejoin": "strokeLinejoin",
+  "stroke-linecap": "strokeLinecap",
+  "stroke-width": "strokeWidth",
+  "fill-rule": "fillRule",
+};
+
+function attribsToProps(el: cheerio.TagElement): any {
+  const { attribs } = el;
+  const result: any = {};
+
+  for (let attrib of Object.keys(attribs)) {
+    const prop = SVG_ATTRIB_TO_PROP_MAP[attrib];
+
+    if (!prop) {
+      throw new Error(`Unknown SVG attribute '${attrib}' in <${el.tagName}>!`);
+    }
+
+    result[prop] = attribs[attrib];
+  }
+
+  return result;
+}
+
+function serializeSvgSymbolElement(
+  $: cheerio.Root,
+  el: cheerio.TagElement
+): SvgSymbolElement {
+  let children = onlyTags(el.children).map((child) =>
+    serializeSvgSymbolElement($, child)
+  );
+  const { tagName } = el;
+  if (isSupportedSvgTag(tagName)) {
+    return {
+      tagName,
+      props: attribsToProps(el) as any,
+      children,
+    };
+  }
+  throw new Error(`Unsupported SVG element: <${tagName}>`);
 }
 
 function getSvgPixelDimension($: cheerio.Root, attr: string): number {
@@ -35,7 +108,7 @@ function getSvgPixelDimension($: cheerio.Root, attr: string): number {
   const match = value.match(/^(\d+)px$/);
   if (!match) {
     throw new Error(
-      `unable to parse <svg> ${attr} attribute value '${value}'!`
+      `Unable to parse <svg> ${attr} attribute value '${value}'!`
     );
   }
   return parseInt(match[1]);
@@ -53,19 +126,17 @@ export function build() {
       const $ = cheerio.load(svgMarkup);
       const width = getSvgPixelDimension($, "width");
       const height = getSvgPixelDimension($, "height");
-      const g = $("svg > g");
-      removeAttrIfNotNone("fill", $, g);
-      removeAttrIfNotNone("stroke", $, g);
+      const svgEl = $("svg");
       const name = path.basename(filename, SVG_EXT);
-      const svg = g.html();
-      if (!svg) {
-        throw new Error(`${filename} has no <g> with child elements!`);
-      }
+      const layers = onlyTags(svgEl.children()).map((ch) =>
+        serializeSvgSymbolElement($, ch)
+      );
+
       const symbol: SvgSymbolData = {
         name,
-        svg,
         width,
         height,
+        layers,
       };
       vocab.push(symbol);
     }