How to get sourceFile with parentNode set?

[octref]

TypeScript Version: 2.2.1

I'm looking at the Compiler API and trying to figure out a way to parse a object literal like so:

export default {
  name: 'foo',
  props: ['bar', 'baz'],
  methods: {
    a () { return 1; },
    b () { return 2; }
  }
}

// Want to get object like this:
const info = {
  name: 'foo',
  props: ['bar', 'baz'],
  methods: ['a', 'b']
}

When I try to do it this way:

let program = ts.createProgram(['test.ts'], {
  target: ts.ScriptTarget.ES5, module: ts.ModuleKind.CommonJS
});
const sourceFile = program.getSourceFile('test.ts');
const exportDefaultObject = find(sourceFile.statements, st => st.kind === ts.SyntaxKind.ExportAssignment &&
  (st as ts.ExportAssignment).expression.kind === ts.SyntaxKind.ObjectLiteralExpression);
ts.forEachChild((exportDefaultObject as ts.ExportAssignment).expression, (literal: ts.ObjectLiteralExpression) => {
  const children = literal.getChildren();
  ...
}

literal.getChildren() or literal.getText() throws exception:

TypeError: Cannot read property 'text' of undefined

However, if I'm creating the sourceFile this way:

const sourceFile = ts.createSourceFile('test.ts', fs.readFileSync('test.ts').toString(), ts.ScriptTarget.ES5, true);

The same code works fine.

However, with setParentNodes as false, it throws same exception Cannot read property 'text'.

Full Code: https://github.com/octref/vueinfo/blob/master/index.ts#L13-L25

So my two questions are:

1. What's the difference between these two ways of creating sourceFile, and why am I getting Cannot read property 'text' in one of them?
2. Is there anyway I can use program.getSourceFile with setParentNodes, so I can access the AST behind it?

[ajafff]

Call program.getTypeChecker(). This set's the parent property on all nodes. The result can be ignored.

[octref]

@ajafff It worked! Wondering why the lack of parent property would cause property text not set, though.

[ajafff]

node.getText() internally does something like node.getSouceFile().text.substring(start, end)

getSourceFile() walks up the parent chain until it finds ts.SourceFile or undefined

you could avoid that by passing the sourceFile to getText, getChildren, getStart, etc ... basically every function or method that has an optional sourceFile parameter (which you should do anyways to avoid unnecessary cpu work)

node.getText(sourceFile); // works even if parent is not set

[octref]

Oh I see -- but TypeChecker seems pretty useful too.
Thanks for the detailed explanation. I guess I'll always pass the sourceFile as a rule of thumb.