React-native-uri no longer well supported - Can react-native-svg support SvgXmlData instead?

[etaiklein]

Feature Request

React-native-uri no longer seems supported (last commit was in 2018 and many open PRs) - read more

Can react-native-community pull in this use case or otherwise take over and support this library?

Why it is needed

React-native-svg-uri is unique because it allows rendering SVGs from a data string. This is crucial for anyone composing their svgs on the server. (svgXmlData)

react-native-svg-uri currently also supports rendering a static image. IMO, react-native-uri doesn't actually need to support fetching from a static file since react-native-svg-transformer fills that niche.

Solutions

One idea is to clone react-native-svg-uri into react-native-community/react-native-svg-uri, merge in the current existing pull requests and do minor bug fixes support the last few RN versions.

Another idea is to create a new SVG data rendering component from scratch inside react-native-svg import {SvgXmlData} from 'react-native-svg'; ... <SvgXmlData source={'svg'} />

[msand]

Perhaps something like this SvgFromXml.js:

import * as React from "react";
import { parse } from "svg-parser";
import {
  Circle,
  ClipPath,
  Defs,
  Ellipse,
  G,
  Image,
  Line,
  LinearGradient,
  Mask,
  Path,
  Pattern,
  Polygon,
  Polyline,
  RadialGradient,
  Rect,
  Stop,
  Svg,
  Symbol,
  Text,
  TextPath,
  TSpan,
  Use
} from "react-native-svg";

const tagNameToTag = {
  svg: Svg,
  circle: Circle,
  ellipse: Ellipse,
  g: G,
  text: Text,
  tspan: TSpan,
  textPath: TextPath,
  path: Path,
  polygon: Polygon,
  polyline: Polyline,
  line: Line,
  rect: Rect,
  use: Use,
  image: Image,
  symbol: Symbol,
  defs: Defs,
  linearGradient: LinearGradient,
  radialGradient: RadialGradient,
  stop: Stop,
  clipPath: ClipPath,
  pattern: Pattern,
  mask: Mask
};

const upperCase = (match, letter) => letter.toUpperCase();

const camelCase = phrase => phrase.replace(/-([a-z])/g, upperCase);

function transformStyle(string) {
  const style = {};
  const declarations = string.split(";");
  for (let i = 0, l = declarations.length; i < l; i++) {
    const declaration = declarations[i].split(":");
    const property = declaration[0];
    const value = declaration[1];
    style[camelCase(property.trim())] = value.trim();
  }
  return style;
}

function camelCaseProps(properties) {
  const { style } = properties;
  const props = {};
  for (let property in properties) {
    if (properties.hasOwnProperty(property)) {
      props[camelCase(property)] = properties[property];
    }
  }
  if (style) {
    props.style = transformStyle(style);
  }
  return props;
}

function childToSvg(child, i) {
  const { tagName, properties, children } = child;
  const Tag = tagNameToTag[tagName];
  return (
    <Tag key={i} {...camelCaseProps(properties)}>
      {children.map(childToSvg)}
    </Tag>
  );
}

function SVGroot({ root, override }) {
  const { properties, children } = root;
  return (
    <Svg {...camelCaseProps(properties)} {...override}>
      {children.map(childToSvg)}
    </Svg>
  );
}

export function SvgFromXml({ xml, ...props }) {
  try {
    const hast = parse(xml);
    return <SVGroot root={hast.children[0]} override={props} />;
  } catch (e) {
    console.log(e);
    return null;
  }
}

Example App.js:

import * as React from "react";
import { SvgFromXml } from "./SvgFromXml";

const xml = `
  <svg width="100%" height="100%" viewBox="0 0 32 32">
    <path
      fill-rule="evenodd"
      clip-rule="evenodd"
      fill="url(#paint0_linear)"
      d="M4 0C1.79086 0 0 1.79086 0 4V28C0 30.2091 1.79086 32 4 32H28C30.2091 32 32 30.2091 32 28V4C32 1.79086 30.2091 0 28 0H4ZM17 6C17 5.44772 17.4477 5 18 5H20C20.5523 5 21 5.44772 21 6V25C21 25.5523 20.5523 26 20 26H18C17.4477 26 17 25.5523 17 25V6ZM12 11C11.4477 11 11 11.4477 11 12V25C11 25.5523 11.4477 26 12 26H14C14.5523 26 15 25.5523 15 25V12C15 11.4477 14.5523 11 14 11H12ZM6 18C5.44772 18 5 18.4477 5 19V25C5 25.5523 5.44772 26 6 26H8C8.55228 26 9 25.5523 9 25V19C9 18.4477 8.55228 18 8 18H6ZM24 14C23.4477 14 23 14.4477 23 15V25C23 25.5523 23.4477 26 24 26H26C26.5523 26 27 25.5523 27 25V15C27 14.4477 26.5523 14 26 14H24Z"
    />
    <defs>
      <linearGradient
        id="paint0_linear"
        x1="0"
        y1="0"
        x2="8.46631"
        y2="37.3364"
        gradient-units="userSpaceOnUse">
        <stop offset="0" stop-color="#FEA267" />
        <stop offset="1" stop-color="#E75A4C" />
      </linearGradient>
    </defs>
  </svg>
`;

export default () => <SvgFromXml xml={xml} />;

[msand]

With uri support:

import React, { Component, useState, useEffect, useMemo } from "react";
import {
  Circle,
  ClipPath,
  Defs,
  Ellipse,
  G,
  Image,
  Line,
  LinearGradient,
  Mask,
  Path,
  Pattern,
  Polygon,
  Polyline,
  RadialGradient,
  Rect,
  Stop,
  Svg,
  Symbol,
  Text,
  TextPath,
  TSpan,
  Use
} from "react-native-svg";

export const tags = {
  svg: Svg,
  circle: Circle,
  ellipse: Ellipse,
  g: G,
  text: Text,
  tspan: TSpan,
  textPath: TextPath,
  path: Path,
  polygon: Polygon,
  polyline: Polyline,
  line: Line,
  rect: Rect,
  use: Use,
  image: Image,
  symbol: Symbol,
  defs: Defs,
  linearGradient: LinearGradient,
  radialGradient: RadialGradient,
  stop: Stop,
  clipPath: ClipPath,
  pattern: Pattern,
  mask: Mask
};

export function astToReact(child, i) {
  if (typeof child === "object") {
    const { Tag, props, children } = child;
    return (
      <Tag key={i} {...props}>
        {children.map(astToReact)}
      </Tag>
    );
  }
  return child;
}

export function SvgAst({ ast, override }) {
  const { props, children } = ast;
  return (
    <Svg {...props} {...override}>
      {children}
    </Svg>
  );
}

export function SvgXml({ xml, ...props }) {
  const ast = useMemo(() => xml && parse(xml), [xml]);
  return (ast && <SvgAst ast={ast} override={props} />) || null;
}

async function fetchText(uri) {
  const response = await fetch(uri);
  return await response.text();
}

const err = console.error.bind(console);

export function SvgUri({ uri, ...props }) {
  const [xml, setXml] = useState();
  useEffect(() => {
    fetchText(uri)
      .then(setXml)
      .catch(err);
  }, [uri]);
  return (xml && <SvgXml xml={xml} {...props} />) || null;
}

export class SvgFromXml extends Component {
  state = {};
  componentDidMount() {
    const { xml } = this.props;
    this.parse(xml);
  }
  componentDidUpdate(prevProps) {
    const { xml } = this.props;
    if (xml !== prevProps.xml) {
      this.parse(xml);
    }
  }
  parse(xml) {
    try {
      const ast = parse(xml);
      this.setState({ ast });
    } catch (e) {
      console.error(e);
    }
  }
  render() {
    const { ast } = this.state;
    return ast ? <SvgAst ast={ast} override={this.props} /> : null;
  }
}

export class SvgFromUri extends Component {
  state = {};
  componentDidMount() {
    const { uri } = this.props;
    this.fetch(uri);
  }
  componentDidUpdate(prevProps) {
    const { uri } = this.props;
    if (uri !== prevProps.uri) {
      this.fetch(uri);
    }
  }
  async fetch(uri) {
    try {
      const xml = await fetchText(uri);
      this.setState({ xml });
    } catch (e) {
      console.error(e);
    }
  }
  render() {
    const { xml } = this.state;
    return xml ? <SvgFromXml xml={xml} {...this.props} /> : null;
  }
}

const upperCase = (match, letter) => letter.toUpperCase();

const camelCase = phrase => phrase.replace(/-([a-z])/g, upperCase);

export function getStyle(string) {
  const style = {};
  const declarations = string.split(";");
  for (let i = 0, l = declarations.length; i < l; i++) {
    const declaration = declarations[i].split(":");
    const property = declaration[0];
    const value = declaration[1];
    style[camelCase(property.trim())] = value.trim();
  }
  return style;
}

// slimmed down parser based on https://github.com/Rich-Harris/svg-parser

function locate(source, search) {
  const lines = source.split("\n");
  for (let line = 0, l = lines.length; line < l; line++) {
    const { length } = lines[line];
    if (search < length) {
      return { line, column: search };
    } else {
      search -= length;
    }
  }
}

const validNameCharacters = /[a-zA-Z0-9:_-]/;
const whitespace = /[\s\t\r\n]/;
const quotemark = /['"]/;

function repeat(str, i) {
  let result = "";
  while (i--) result += str;
  return result;
}

export function parse(source) {
  const length = source.length;
  let currentElement = null;
  let state = metadata;
  let children = null;
  let root = null;
  let stack = [];

  function error(message) {
    const { line, column } = locate(source, i);
    const before = source
      .slice(0, i)
      .replace(/^\t+/, match => repeat("  ", match.length));
    const beforeLine = /(^|\n).*$/.exec(before)[0];
    const after = source.slice(i);
    const afterLine = /.*(\n|$)/.exec(after)[0];

    const snippet = `${beforeLine}${afterLine}\n${repeat(
      " ",
      beforeLine.length
    )}^`;

    throw new Error(
      `${message} (${line}:${column}). If this is valid SVG, it's probably a bug. Please raise an issue\n\n${snippet}`
    );
  }

  function metadata() {
    while (
      (i < length && source[i] !== "<") ||
      !validNameCharacters.test(source[i + 1])
    ) {
      i++;
    }

    return neutral();
  }

  function neutral() {
    let text = "";
    while (i < length && source[i] !== "<") text += source[i++];

    if (/\S/.test(text)) {
      children.push(text);
    }

    if (source[i] === "<") {
      return openingTag;
    }

    return neutral;
  }

  function openingTag() {
    const char = source[i];

    if (char === "?") return neutral; // <?xml...

    if (char === "!") {
      if (source.slice(i + 1, i + 3) === "--") return comment;
      if (source.slice(i + 1, i + 8) === "[CDATA[") return cdata;
      if (/doctype/i.test(source.slice(i + 1, i + 8))) return neutral;
    }

    if (char === "/") return closingTag;

    const tag = getName();
    const props = {};
    const element = {
      tag,
      props,
      children: [],
      Tag: tags[tag]
    };

    if (currentElement) {
      children.push(element);
    } else {
      root = element;
    }

    getAttributes(props);

    const { style } = props;
    if (style) {
      props.style = getStyle(style);
    }

    let selfClosing = false;

    if (source[i] === "/") {
      i += 1;
      selfClosing = true;
    }

    if (source[i] !== ">") {
      error("Expected >");
    }

    if (!selfClosing) {
      currentElement = element;
      ({ children } = element);
      stack.push(element);
    }

    return neutral;
  }

  function comment() {
    const index = source.indexOf("-->", i);
    if (!~index) error("expected -->");

    i = index + 2;
    return neutral;
  }

  function cdata() {
    const index = source.indexOf("]]>", i);
    if (!~index) error("expected ]]>");

    i = index + 2;
    return neutral;
  }

  function closingTag() {
    const tag = getName();

    if (!tag) error("Expected tag name");

    if (tag !== currentElement.tag) {
      error(
        `Expected closing tag </${tag}> to match opening tag <${
          currentElement.tag
        }>`
      );
    }

    if (source[i] !== ">") {
      error("Expected >");
    }

    stack.pop();
    currentElement = stack[stack.length - 1];
    if (currentElement) {
      ({ children } = currentElement);
    }

    return neutral;
  }

  function getName() {
    let name = "";
    while (i < length && validNameCharacters.test(source[i]))
      name += source[i++];

    return name;
  }

  function getAttributes(props) {
    while (i < length) {
      if (!whitespace.test(source[i])) return;
      allowSpaces();

      const name = getName();
      if (!name) return;

      let value = true;

      allowSpaces();
      if (source[i] === "=") {
        i += 1;
        allowSpaces();

        value = getAttributeValue();
        if (!isNaN(value) && value.trim() !== "") value = +value; // TODO whitelist numeric attributes?
      }

      props[camelCase(name)] = value;
    }
  }

  function getAttributeValue() {
    return quotemark.test(source[i])
      ? getQuotedAttributeValue()
      : getUnquotedAttributeValue();
  }

  function getUnquotedAttributeValue() {
    let value = "";
    do {
      const char = source[i];
      if (char === " " || char === ">" || char === "/") {
        return value;
      }

      value += char;
      i += 1;
    } while (i < length);

    return value;
  }

  function getQuotedAttributeValue() {
    const quotemark = source[i++];

    let value = "";
    let escaped = false;

    while (i < length) {
      const char = source[i++];
      if (char === quotemark && !escaped) {
        return value;
      }

      if (char === "\\" && !escaped) {
        escaped = true;
      }

      value += escaped ? `\\${char}` : char;
      escaped = false;
    }
  }

  function allowSpaces() {
    while (i < length && whitespace.test(source[i])) i += 1;
  }

  let i = 0;
  while (i < length) {
    if (!state) error("Unexpected character");
    state = state();
    i += 1;
  }

  if (state !== neutral) {
    error("Unexpected end of input");
  }

  root.children = root.children.map(astToReact);

  return root;
}

[msand]

@etaiklein I've optimized the implementation a bit, and added hooks based ones as well.

[etaiklein]

Amazing work and quick response - thank you so much!

I was able to run the example in the readme no problem. However, I found a few cases blocking me from using my existing web svgs:

Failure 1: Adding inline style to text

<svg width="32" height="32" viewBox="0 0 32 32">
  <text x="1" y="20" style="fill:red;">TEST</text>
</svg>

TypeError: Cannot read property 'trim' of undefined

Failure 2: Including a