storybook/addons/storysource/src/loader/parse-helpers.js

const { toId } = require('@storybook/router/utils');

const STORIES_OF = 'storiesOf';

function pushParts(source, parts, from, to) {
  const start = source.slice(from, to);
  parts.push(start);

  const end = source.slice(to);
  parts.push(end);
}

function getKindFromStoryOfNode(object) {
  if (object.arguments.length < 1) {
    return '';
  }

  const kindArgument = object.arguments[0];

  if (kindArgument.type === 'Literal' || kindArgument.type === 'StringLiteral') {
    return kindArgument.value;
  }

  if (kindArgument.type === 'TemplateLiteral') {
    // we can generate template, but it will not be a real value
    // until the full template compilation. probably won't fix.
    return '';
  }

  // other options may include some complex usages.
  return '';
}

function findRelatedKind(object) {
  if (!object || !object.callee) {
    return '';
  }

  if (object.callee.name === STORIES_OF) {
    return getKindFromStoryOfNode(object);
  }

  return findRelatedKind(object.callee.object);
}

export function patchNode(node) {
  if (node.range && node.range.length === 2 && node.start === undefined && node.end === undefined) {
    const [start, end] = node.range;

    // eslint-disable-next-line no-param-reassign
    node.start = start;
    // eslint-disable-next-line no-param-reassign
    node.end = end;
  }

  if (!node.range && node.start !== undefined && node.end !== undefined) {
    // eslint-disable-next-line no-param-reassign
    node.range = [node.start, node.end];
  }

  return node;
}

export function handleADD(node, parent, adds) {
  if (!node.property || !node.property.name || node.property.name.indexOf('add') !== 0) {
    return;
  }

  const addArgs = parent.arguments;

  if (!addArgs || addArgs.length < 2) {
    return;
  }

  const storyName = addArgs[0];
  const lastArg = addArgs[addArgs.length - 1];

  if (storyName.type !== 'Literal' && storyName.type !== 'StringLiteral') {
    // if story name is not literal, it's much harder to extract it
    return;
  }

  const kind = findRelatedKind(node.object) || '';
  if (kind && storyName.value) {
    const key = toId(kind, storyName.value);

    // eslint-disable-next-line no-param-reassign
    adds[key] = {
      // Debug: code: source.slice(storyName.start, lastArg.end),
      startLoc: {
        col: storyName.loc.start.column,
        line: storyName.loc.start.line,
      },
      endLoc: {
        col: lastArg.loc.end.column,
        line: lastArg.loc.end.line,
      },
    };
  }
}

export function handleSTORYOF(node, parts, source, lastIndex) {
  if (!node.callee || !node.callee.name || node.callee.name !== STORIES_OF) {
    return lastIndex;
  }

  parts.pop();
  pushParts(source, parts, lastIndex, node.end);
  return node.end;
}