exports-loader/dist/utils.js

exports loader module for webpack

"use strict";

Object.defineProperty(exports, "__esModule", {
  value: true
});
exports.getExports = getExports;
exports.renderExports = renderExports;
function forError(item) {
  return typeof item === "string" ? item : `\n${JSON.stringify(item, null, " ")}\n`;
}
function splitCommand(command) {
  const result = command.split("|").map(item => item.split(" ")).reduce((acc, val) => acc.concat(val), []);
  for (const item of result) {
    if (!item) {
      throw new Error(`Invalid command "${item}" in "${command}" for exports. There must be only one separator: " ", or "|"`);
    }
  }
  return result;
}
function resolveExports(type, item) {
  let result;
  if (typeof item === "string") {
    const noWhitespaceItem = item.trim();
    if (noWhitespaceItem.length === 0) {
      throw new Error(`Invalid "${item}" value for export`);
    }
    const splittedItem = splitCommand(noWhitespaceItem);
    if (splittedItem.length > 3) {
      throw new Error(`Invalid "${item}" value for export`);
    }
    if (splittedItem.length === 1) {
      result = {
        syntax: type === "module" ? "named" : "multiple",
        name: splittedItem[0],
        // eslint-disable-next-line no-undefined
        alias: undefined
      };
    } else {
      result = {
        syntax: splittedItem[0],
        name: splittedItem[1],
        alias:
        // eslint-disable-next-line no-undefined
        typeof splittedItem[2] !== "undefined" ? splittedItem[2] : undefined
      };
    }
  } else {
    result = {
      syntax: type === "module" ? "named" : "multiple",
      ...item
    };
  }
  if (!["default", "named", "single", "multiple"].includes(result.syntax)) {
    throw new Error(`Unknown "${result.syntax}" syntax export in "${forError(item)}" value`);
  }
  if (["default", "single"].includes(result.syntax) && typeof result.alias !== "undefined") {
    throw new Error(`The "${result.syntax}" syntax can't have "${result.alias}" alias in "${forError(item)}" value`);
  }
  if (type === "commonjs") {
    if (result.syntax === "default" || result.syntax === "named") {
      throw new Error(`The "${type}" format can't be used with the "${result.syntax}" syntax export in "${forError(item)}" value`);
    }
  }
  if (type === "module") {
    if (result.syntax === "single" || result.syntax === "multiple") {
      throw new Error(`The "${type}" format can't be used with the "${result.syntax}" syntax export in "${forError(item)}" value`);
    }
  }
  return result;
}
function getIdentifiers(array) {
  return array.reduce((accumulator, item) => {
    if (typeof item.alias !== "undefined") {
      accumulator.push({
        type: "alias",
        value: item.alias
      });
      return accumulator;
    }
    accumulator.push({
      type: "name",
      value: item.name
    });
    return accumulator;
  }, []);
}
function getExports(type, exports) {
  let result;
  const exportItems = typeof exports === "string" && exports.includes(",") ? exports.split(",") : exports;
  if (Array.isArray(exportItems)) {
    result = exportItems.map(item => resolveExports(type, item));
  } else {
    result = [resolveExports(type, exportItems)];
  }
  const hasMultipleDefault = result.filter(({
    syntax
  }) => syntax === "default" || syntax === "single");
  if (hasMultipleDefault.length > 1) {
    throw new Error(`The "${type}" format can't have multiple "${type === "module" ? "default" : "single"}" exports in "\n${JSON.stringify(exports, null, " ")}\n" value`);
  }
  const identifiers = getIdentifiers(result);
  const duplicates = duplicateBy(identifiers, "value");
  if (duplicates.length > 0) {
    throw new Error(`Duplicate ${duplicates.map(identifier => `"${identifier.value}" (as "${identifier.type}")`).join(", ")} identifiers found in "\n${JSON.stringify(exports, null, " ")}\n" value`);
  }
  return result;
}
function duplicateBy(array, key) {
  return array.filter((a, aIndex) => array.filter((b, bIndex) => b[key] === a[key] && aIndex !== bIndex).length > 0);
}
function renderExports(loaderContext, type, exports) {
  let code = "";
  const defaultExport = exports.filter(({
    syntax
  }) => syntax === "default" || syntax === "single");
  const namedExports = exports.filter(({
    syntax
  }) => syntax === "named" || syntax === "multiple");
  if (defaultExport.length > 0) {
    // eslint-disable-next-line default-case
    switch (type) {
      case "commonjs":
        code += "module.exports = ";
        break;
      case "module":
        code += "export default ";
        break;
    }
    code += `${defaultExport[0].name};\n`;
  }
  if (namedExports.length > 0) {
    // eslint-disable-next-line default-case
    switch (type) {
      case "commonjs":
        code += "module.exports = {\n";
        break;
      case "module":
        code += "export {\n";
        break;
    }
    namedExports.forEach((namedExport, i) => {
      const needComma = i < namedExports.length - 1;
      const {
        name
      } = namedExport;
      // eslint-disable-next-line no-undefined
      const alias = namedExport.alias || undefined;
      code += `  ${type === "commonjs" ? alias ? `${JSON.stringify(alias)}: (${name})` : `${name}` : `${name}${alias ? ` as ${alias}` : ""}`}${needComma ? ",\n" : ""}`;
    });
    code += "\n};\n";
  }
  return code;
}