owncast/build/javascript/node_modules/postcss-inline-svg/lib/parseDeclValue.js

const valueParser = require("postcss-value-parser");

const { stringify } = valueParser;

function getUrl(nodes) {
  let url = "";
  let urlEnd = 0;

  for (let i = 0; i < nodes.length; i += 1) {
    const node = nodes[i];
    if (node.type === "string") {
      if (i !== 0) {
        throw Error(`Invalid "svg-load(${stringify(nodes)})" definition`);
      }
      url = node.value;
      urlEnd = i + 1;
      break;
    }
    if (node.type === "div" && node.value === ",") {
      if (i === 0) {
        throw Error(`Invalid "svg-load(${stringify(nodes)})" definition`);
      }
      urlEnd = i;
      break;
    }
    url += stringify(node);
    urlEnd += 1;
  }

  return {
    url,
    urlEnd
  };
}

function getParamChunks(nodes) {
  const list = [];
  const lastArg = nodes.reduce((arg, node) => {
    if (node.type === "word" || node.type === "string") {
      return arg + node.value;
    }
    if (node.type === "space") {
      return arg + " ";
    }
    if (node.type === "div" && node.value === ",") {
      list.push(arg);
      return "";
    }
    return arg + stringify(node);
  }, "");

  return list.concat(lastArg);
}

function splitParams(list) {
  const params = {};

  list.reduce((sep, arg) => {
    if (!arg) {
      throw Error(`Expected parameter`);
    }

    if (!sep) {
      if (arg.indexOf(":") !== -1) {
        sep = ":";
      } else if (arg.indexOf("=") !== -1) {
        sep = "=";
      } else {
        throw Error(`Expected ":" or "=" separator in "${arg}"`);
      }
    }

    const pair = arg.split(sep);
    if (pair.length !== 2) {
      throw Error(`Expected "${sep}" separator in "${arg}"`);
    }
    params[pair[0].trim()] = pair[1].trim();

    return sep;
  }, null);

  return params;
}

function getLoader(parsedValue, valueNode) {
  if (!valueNode.nodes.length) {
    throw Error(`Invalid "svg-load()" statement`);
  }

  // parse url
  const { url, urlEnd } = getUrl(valueNode.nodes);

  // parse params
  const paramsNodes = valueNode.nodes.slice(urlEnd + 1);
  const params =
    urlEnd !== valueNode.nodes.length
      ? splitParams(getParamChunks(paramsNodes))
      : {};

  return {
    url,
    params,
    valueNode,
    parsedValue
  };
}

function getInliner(parsedValue, valueNode) {
  if (!valueNode.nodes.length) {
    throw Error(`Invalid "svg-inline()" statement`);
  }
  const name = valueNode.nodes[0].value;

  return {
    name,
    valueNode,
    parsedValue
  };
}

module.exports = function parseDeclValue(value) {
  const loaders = [];
  const inliners = [];
  const parsedValue = valueParser(value);

  parsedValue.walk(valueNode => {
    if (valueNode.type === "function") {
      if (valueNode.value === "svg-load") {
        loaders.push(getLoader(parsedValue, valueNode));
      } else if (valueNode.value === "svg-inline") {
        inliners.push(getInliner(parsedValue, valueNode));
      }
    }
  });

  return {
    loaders,
    inliners
  };
};