addItem method

Map<M, T>? addItem(
  1. M key,
  2. T value
)

添加元素到map中 key元素key value元素value

Implementation

Map<M, T>? addItem(M key, T value) {
  if (key == null || value == null) {
    return this;
  }
  this?[key] = value;
  return this;
}