Using ReactJS + Material-UI, I have an array called colors and contains strings of different colors. Say for example the array colors has 3 color strings: "white", "blue", "green. Then I would like to render each color string has a <MenuItem/> inside a <DropDownMenu/> (). And once a <MenuItem/> is selected, I'd like to console log that particular color like, say chose "white": console.log("white").

So I used .forEach yet the does not show any strings and it is empty. What could I be doing wrong?

Here is the code:

  constructor() {
    super()

    this.state = {
      value: 1,
    }
  }

  dropDownColorChange(event, index, value) {
    this.setState({value: value})
    //Not sure how to implement here dynamically based on array size. Would like to console.log the color string of the selected
  }

  render() {
    var colors = ["white", "blue", "green"] //would be able to handle any array size


    return (
             <div>
               <DropDownMenu
                value={this.state.valueTwo}
                onChange={this.dropDownColorChange}
              >
                {
                    <MenuItem value={1} primaryText="Select" />
                  colors.forEach(color => {
                    <MenuItem primaryText={color}/>
                  })
                }
              </DropDownMenu>
             </div>
    )
  }

Thank you

Using ReactJS + Material-UI, I have an array called colors and contains strings of different colors. Say for example the array colors has 3 color strings: "white", "blue", "green. Then I would like to render each color string has a <MenuItem/> inside a <DropDownMenu/> (http://www.material-ui./#/ponents/dropdown-menu). And once a <MenuItem/> is selected, I'd like to console log that particular color like, say chose "white": console.log("white").

So I used .forEach yet the does not show any strings and it is empty. What could I be doing wrong?

Here is the code:

  constructor() {
    super()

    this.state = {
      value: 1,
    }
  }

  dropDownColorChange(event, index, value) {
    this.setState({value: value})
    //Not sure how to implement here dynamically based on array size. Would like to console.log the color string of the selected
  }

  render() {
    var colors = ["white", "blue", "green"] //would be able to handle any array size


    return (
             <div>
               <DropDownMenu
                value={this.state.valueTwo}
                onChange={this.dropDownColorChange}
              >
                {
                    <MenuItem value={1} primaryText="Select" />
                  colors.forEach(color => {
                    <MenuItem primaryText={color}/>
                  })
                }
              </DropDownMenu>
             </div>
    )
  }

Thank you

• javascript
• css
• reactjs
• material-ui

2 Answers 2

You've almost got it right. You have to map over available colors and return a MenuItem for each color:

const colors = ['white', 'blue', 'green'];

class ColorChanger extends Component {
  constructor() {
    super();

    this.state = {
      selectedColorValue: 1,
    };
  }

  handleColorChange(event, index, value) {
    console.log(`You have selected ${colors[value]} color`);

    this.setState({
      selectedColorValue: value
    });
  }

  render() {
    return (
      <div>
        <DropDownMenu value={this.state.selectedColorValue} onChange={this.handleColorChange}>
          {colors.map((color, index) =>
            <MenuItem key={index} value={index} primaryText={color} />
          )}
        </DropDownMenu>
      </div>
    );
  }
}

map (contrary to forEach) returns an array where each element is the return value of predicate function. In your case it returns a <MenuItem />.

I used the react hook to set the menu items on clicking my menu icon and I also set the value I want to pass to my action method.

const [menuItems, setMenuItems] = React.useState<IMenuItem[]>();
const [menuValue, setMenuValue] = React.useState<IMenuValue>();

const handleClickMenu = (
    event: React.MouseEvent<HTMLElement>,
    value: IMenuValue,
  ) => {
    setMenuItems(value.menuItems);
    setMenuTransaction(value);

    setMenuAnchorEl(event.currentTarget);
  };


return (

// ... code ...
<PositionedVertMenu
 data-testid={`menu`}
 open={Boolean(menuAnchorEl)}
 anchorEl={menuAnchorEl}
 onClick={(event: React.MouseEvent<HTMLElement>) => handleClickMenu(event, value)}
 onClose={handleCloseMenu}
>
  {menuValue &&
   menuItems?.map((option, menuIndex) => (
    <MenuItem
     data-testid={`menu-item-${menuIndex}`}
     onClick={() => option.action(menuValue, handleCloseMenu)}
    >
     <Typography>{translate(option.text)}</Typography>
    </MenuItem>
   ))}
 </PositionedVertMenu>
)