propOrCrash (method)

propOrCrash

• propOrCrash<K, R>(key, errorFactory?): R

• Get a field from a wrapped object. Crash if the field is missing or empty, or opt instance is None. Shortcut of Opt.prop + Opt.orCrash.

  Type Parameters

  • K extends string | number | symbol

  • R extends {}

  Parameters

  • key: K

  • Optional errorFactory: string | ((key) => string | Error)

  Returns R

  Example

  interface A {x?: number;}
  
  const aFull: A = {x: 4};
  opt(aFull).propOrCrash('x'); // 4
  
  const aEmpty: A = {};
  opt(aEmpty).propOrCrash('x'); // crash
  
  // with custom error: "Custom error: x is missing"
  opt(aEmpty).propOrCrash('x', 'Custom error: x is missing'); // crash 
  opt(aEmpty).propOrCrash('x', key => `Custom error: ${key} is missing`); // crash
  opt(aEmpty).propOrCrash('x', key => new Error(`Custom error: ${key} is missing`)); // crash