Options, Strict Mode & Errors

Options are passed to the constructor (or create), or set later via the .options property:

const n = Notation.create(obj, { strict: true });
n.options = { preserveIndices: true };   // merged onto existing options

Option	Default	Effect
strict	false	throw on missing paths / blocked overwrites instead of failing quietly
preserveIndices	false	keep array indices when removing items (produces sparse arrays)

strict

With strict off (the default), missing paths resolve to undefined and blocked writes are skipped silently. With strict on, they throw — recommended when working with sensitive data, so failures surface instead of slipping through.

Notation.create({ car: {} }).get('car.model');               // » undefined
Notation.create({ car: {} }, { strict: true }).get('car.model');
// » throws NotationError — "car.model" does not exist

A default value bypasses the throw — it’s an explicit fallback:

Notation.create({ car: {} }, { strict: true }).get('car.model', null);  // » null

strict affects get(), set() (when overwrite is disabled), and remove(). The inspect methods — inspectGet() / inspectRemove() — are exempt; they report has: false rather than throwing.

Regardless of strict, invalid notation syntax and other critical failures always throw.

preserveIndices

Removing an array item splices by default, so later indices shift down. Enable preserveIndices to leave a sparse hole instead:

Notation.create([0, 1, 2]).remove('[1]').value;
// » [0, 2]

Notation.create([0, 1, 2], { preserveIndices: true }).remove('[1]').value;
// » [0, <empty>, 2]

NotationError

All thrown errors are instances of NotationError (a subclass of Error), so you can target them specifically:

import { Notation, NotationError } from 'notation';

try {
  Notation.create({ x: 1 }).filter(['*', '!x.*']);  // integrity failure
} catch (err) {
  if (err instanceof NotationError) {
    console.error('notation problem:', err.message);
  } else {
    throw err;
  }
}

The restrictive option for filter() is covered in Filtering Data.