Function visitSourceFile

src/transform.ts:130–178

(
  ctx: ts.TransformationContext,
  sf: ts.SourceFile,
  opts?: Opts
)

}

function visitSourceFile(
  ctx: ts.TransformationContext,
  sf: ts.SourceFile,
  opts?: Opts
): ts.SourceFile {
  /**
   * Find the 1st node that we can inject hoisted variable. This means:
   * 1. Pass the prologue directive
   * 2. Pass shebang (not a node)
   * 3. Pass top level comments (not a node)
   * 4. Pass React import (bc hoisted var uses React)
   */
  const firstHoistableNodeIndex = sf.statements.findIndex(
    node => isNotPrologueDirective(node) && isReactImport(node, sf)
  );
  // Can't find where to hoist
  if (!~firstHoistableNodeIndex) {
    return sf;
  }

  const hoistedVariables: ts.VariableStatement[] = [];
  const elVisitor = constantElementVisitor(ctx, hoistedVariables);

  // We assume we only care about nodes after React import
  const transformedStatements = sf.statements
    .slice(firstHoistableNodeIndex + 1, sf.statements.length)
    .map(node => ts.visitNode(node, elVisitor));
  if (opts.verbose) {
    console.log(
      `Hoisting ${hoistedVariables.length} elements in ${sf.fileName}:`
    );
    hoistedVariables.forEach(n =>
      console.log(n.declarationList.declarations[0].initializer.getText(sf))
    );
  }

  return ts.updateSourceFileNode(
    sf,
    ts.setTextRange(
      ts.createNodeArray([
        ...sf.statements.slice(0, firstHoistableNodeIndex + 1),
        // Inject hoisted variables
        ...hoistedVariables,
        ...transformedStatements
      ]),
      sf.statements
    )
  );
}

export interface Opts {
  verbose?: boolean;