get-definition-at-position.ts

import ts from 'typescript';
import { visit, type FragmentSpreadNode } from 'graphql';
import { getFragmentsInDocument } from '../gql-ast-util';
import type { AnalysisContext, GetDefinitionAtPosition } from './types';

export function getDefinitionAtPosition(
  ctx: AnalysisContext,
  delegate: GetDefinitionAtPosition,
  fileName: string,
  position: number,
) {
  if (ctx.getScriptSourceHelper().isExcluded(fileName)) return delegate(fileName, position);
  const node = ctx.findAscendantTemplateNode(fileName, position);
  if (!node) return delegate(fileName, position);
  const { resolvedInfo } = ctx.resolveTemplateInfo(fileName, node);
  if (!resolvedInfo) return delegate(fileName, position);
  const { combinedText, getInnerPosition, getSourcePosition } = resolvedInfo;
  const documentNode = ctx.getGraphQLDocumentNode(combinedText);
  if (!documentNode) return delegate(fileName, position);

  try {
    const innerPosition = getInnerPosition(position);
    if (innerPosition.isInOtherExpression) return delegate(fileName, position);
    let fragmentSpreadNodeUnderCursor: FragmentSpreadNode | undefined = undefined;
    visit(documentNode, {
      FragmentSpread: node => {
        if (node.loc!.start <= innerPosition.pos && innerPosition.pos < node.loc!.end) {
          fragmentSpreadNodeUnderCursor = node;
        }
      },
    });
    if (!fragmentSpreadNodeUnderCursor) return delegate(fileName, position);
    const foundFragmentDefinitionNode = getFragmentsInDocument(documentNode).find(
      fragmentDef => fragmentDef.name.value === fragmentSpreadNodeUnderCursor?.name.value,
    );
    if (!foundFragmentDefinitionNode) return delegate(fileName, position);
    const definitionSourcePosition = getSourcePosition(foundFragmentDefinitionNode.name.loc!.start);
    return [
      {
        fileName: definitionSourcePosition.fileName,
        name: foundFragmentDefinitionNode.name.value,
        textSpan: {
          start: definitionSourcePosition.pos,
          length: foundFragmentDefinitionNode.name.loc!.end - foundFragmentDefinitionNode.name.loc!.start,
        },
        kind: ts.ScriptElementKind.unknown,
        containerKind: ts.ScriptElementKind.unknown,
        containerName: '',
      },
    ] satisfies ts.DefinitionInfo[];
  } catch {
    return delegate(fileName, position);
  }
}