如何按字母顺序对下拉菜单项排序？

Question

Is there any way to display options in an alphabetical order in the drop-down menu of Material-UI ?

I know that arrays can be sorted simply using arr.sort() . However, if I do const options = [...].sort() , then I still see unsorted values in the drop-down menu.

const options = [
  {label:"B",value:8033.86},
  {label:"A",value:483.93},
  {label:"Z",value:1246.3},
  {label:"C",value:145.0},
  {label:"E",value:244.5}
]

<Grid item xs={true}>
  <FormControl
      className={this.props.styles.formControl}
      margin="normal">
      <InputLabel shrink htmlFor="distanceTarget-label-placeholder">
          Target:
      </InputLabel>
      <Select
        onChange={(event) => this.props.handleChange("distanceTarget", event)}
        value={this.props.state.distanceTarget}
        input={<Input name="distanceTarget" id="distanceTarget-label-placeholder" />}
        displayEmpty="true"
        name="distanceTarget"
      >
      {options && options.length && options.map((option, i) => {
          return <MenuItem value={option.value} key={i}>{option.label}</MenuItem>
      })}
      </Select>
  </FormControl>
</Grid>

Answer 1

here a simple way to sort the array of objects and you can read the documentation

 const options = [ {label:"B",value:8033.86}, {label:"A",value:483.93}, {label:"Z",value:1246.3}, {label:"C",value:145.0}, {label:"E",value:244.5} ] console.log(options.sort((a, b) => (a.label > b.label) ? 1 : -1)) 

Answer 2

Material-UI is about styles, not logic. First of all, you need to sort your options.

    for (const item in options) {
     console.log(options[item].label)
    }

Its first steps. The second you should try yourself.

Answer 3

When you're dealing with an Array of Objects, you need to tell what determines which one comes first:

function sortAlphabeticallyAscending(a,b){
    if(a.label < b.label) return -1;
    else if (a.label > b.label) return 1;
    else return 0;
}

options.sort(sortAlphabeticallyAscending);

basically, return -1 if you want to say that the index of a is lower than b (ie a comes first), return 1 if you want to say that b comes first, and 0 if you don't want to change the order

See the section compareFunction in the docs...

Answer 4

You have to define the sorting logic as your input array is an array of objects.

More info can be found here

 const options = [ {label:"B",value:8033.86}, {label:"A",value:483.93}, {label:"Z",value:1246.3}, {label:"C",value:145.0}, {label:"E",value:244.5} ]; const objComparator = function(a, b) { if (a.label < b.label) { return -1; } if (a.label > b.label) { return 1; } return 0; }; options.sort(objComparator);