prettier-plugin-imports/src/utils/get-sorted-nodes-by-import-order.ts

A prettier plugins to sort imports in provided RegEx order

import { newLineNode, THIRD_PARTY_MODULES_SPECIAL_WORD } from '../constants';
import { getImportNodesMatchedGroup } from './get-import-nodes-matched-group';
import { getSortedImportSpecifiers } from './get-sorted-import-specifiers';
import { getSortedNodesGroup } from './get-sorted-nodes-group';
import {
  isCustomGroupSeparator,
  testingOnly,
} from './normalize-plugin-options';
import type {
  GetSortedNodesByImportOrder,
  ImportGroups,
  ImportOrLine,
} from '../types';

/**
 * This function returns the given nodes, sorted in the order as indicated by
 * the importOrder array from the given options. The plugin considers these
 * import nodes as local import declarations.
 *
 * @param originalNodes A subset (of all import nodes) that should be sorted.
 * @param options Options to influence the behavior of the sorting algorithm.
 */
export const getSortedNodesByImportOrder: GetSortedNodesByImportOrder = (
  originalNodes,
  { importOrder, importOrderCaseSensitive },
) => {
  if (
    process.env.NODE_ENV === 'test' &&
    JSON.stringify(importOrder) !==
      JSON.stringify(testingOnly.normalizeImportOrderOption(importOrder))
  ) {
    throw new Error(
      'API Misuse: getSortedNodesByImportOrder::importOrder option already should be normalized.',
    );
  }

  const finalNodes: ImportOrLine[] = [];

  const importOrderGroups = importOrder.reduce<ImportGroups>(
    (groups, regexp) =>
      // Don't create a new group for explicit import separators
      isCustomGroupSeparator(regexp)
        ? groups
        : {
            ...groups,
            [regexp]: [],
          },
    {},
  );

  // Select just the SPECIAL WORDS and the matchers
  const sanitizedImportOrder = importOrder.filter(
    (group) =>
      !isCustomGroupSeparator(group) &&
      group !== THIRD_PARTY_MODULES_SPECIAL_WORD,
  );

  // Assign import nodes into import order groups
  for (const node of originalNodes) {
    const matchedGroupName = getImportNodesMatchedGroup(
      node,
      sanitizedImportOrder,
    );
    const matchedGroup = importOrderGroups[matchedGroupName];
    if (matchedGroup) {
      matchedGroup.push(node);
    } else {
      throw new Error(
        `Could not find a matching group in importOrder for: "${node.source.value}" on line ${node.source.loc?.start.line}.${node.importKind === 'type' ? ' Did you forget to include "<TYPES>"?' : ''}`,
      );
    }
  }

  for (const group of importOrder) {
    // If it's a custom separator, all we need to do is add a newline
    if (isCustomGroupSeparator(group)) {
      const lastNode = finalNodes[finalNodes.length - 1];
      // Avoid empty new line if first group is empty
      if (!lastNode) {
        continue;
      }
      // Don't add multiple newlines
      if (isNodeANewline(lastNode)) {
        continue;
      }
      finalNodes.push(newLineNode);
      continue;
    }

    const groupNodes = importOrderGroups[group];

    if (groupNodes.length === 0) continue;

    const sortedInsideGroup = getSortedNodesGroup(groupNodes, {
      importOrderCaseSensitive,
    });

    // Sort the import specifiers
    sortedInsideGroup.forEach((node) =>
      getSortedImportSpecifiers(node, { importOrderCaseSensitive }),
    );

    finalNodes.push(...sortedInsideGroup);
  }

  return finalNodes;
};

function isNodeANewline(node: ImportOrLine) {
  return node.type === 'ExpressionStatement';
}