defs.js

export const READ_ONLY = 1
export const DONT_ENUM = 2
export const DONT_DELETE = 4

export function InstallFunctions(object, attributes, functions) {
  for (let i = 0; i < functions.length; i += 2) {
    let field = functions[i]
    let value = functions[i + 1]

    AddNamedProperty(object, field, value, attributes)
  }
}

export function InstallConstants(object, constants) {
  let attributes = DONT_ENUM | DONT_DELETE | READ_ONLY

  for (let i = 0; i < constants.length; i += 2) {
    let field = constants[i]
    let value = constants[i + 1]

    AddNamedProperty(object, field, value, attributes)
  }
}

export function SetUpLockedPrototype(constructor, fields, methods) {
  let prototype = constructor.prototype

  for (let i = 0; i < fields.length; i++) {
    AddNamedProperty(prototype, fields[i], undefined, DONT_ENUM | DONT_DELETE)
  }

  InstallFunctions(prototype, DONT_ENUM | DONT_DELETE | READ_ONLY, methods)
}

function AddNamedProperty(object, field, value, attributes) {
  Object.defineProperty(object, field, {
    value: value,
    configurable: 0 === (attributes & DONT_DELETE),
    enumerable:   0 === (attributes & DONT_ENUM),
    writable:     0 === (attributes & READ_ONLY)
  })
}