React: Почему обновляются пропсы? Когда я не обновляю их?

changeHandler = e => {
    const { target } = e;
    const { name } = target;
    const value = target.type === 'checkbox' ? target.checked : target.value;

    this.setState({
      data: {
        [this.state.id]: {
          [name]: value,
        },
      },
    });
  };

this.setState({
      data: [...this.state.data].forEach((el, i) => {
        if (i == this.state.id) {
          console.log("el", i, el[name], value);
          return (el[name] = value);
        }
      })
    });

changeHandler = e => {
    const { target } = e;
    const { name } = target;
    const value = target.type === 'checkbox' ? target.checked : target.value;

    this.setState({
      data: {
        [this.state.id]: {
          ...this.state.data[this.state.id],
          [name]: value,
        },
      },
    });
  };