My structure:
index.js
--> Filters
--> {list}
Filters contains multiple input elements that set the state in index.js via props.
list displays as you guessed it, a list of elements. I now want to filter this list based on the values returned by the filters. Pretty standard I think and found on millions of sites.
The issue is that I want to make the input onChange function reusable. With only one input in the Filters component I had this (shortened):
<input
value={this.state.anySearch}
onChange={this.handleChange}
/>
handleChange = event => {
const value = event.target.value;
this.setState({ anySearch: value });
};
With multiple inputs I tried this, aka reusable for any input:
handleChange = name => event => {
const value = event.target.value;
this.setState({ name: value });
};
onChange={this.handleChange("anySearch")}
But this doesn't work anymore. State now shows only one letter at a time when console logged.
What is best practice to filter according to multiple different criteria à la kayak, and how do I rewrite the handleChange function without pushing each letter into an array?
handleChange = name => event => {
const value = event.target.value;
this.setState({ name: value });
};
your idea of returning a function is correct, you just have an error when setting the state
this.setState({ name: value });
change it to
this.setState({ [name]: value });
Regarding the second question, you can simply iterate over your array and filter out the objects that match that specific criteria, to avoid unnecessary overhead you can implement a caching mechanism that keep track of the searches the user has already done.
something like this:
function filter(criteria) {
if(cache[criteria]) {
return cache[criteria];
}
cache[criteria] = myArray.filter(elem => elem.criteria === criteria);
return cache[criteria];
}
Related
I am new to ReactJS and pairing it with Material UI is really causing me some roadblocks. I have created a reusable search filter component for my data tables and it worked exactly the way I wanted, but now I want to add a button to clear the field and show the unfiltered results, as well as return the InputSearch component back to its default state so it will display the label inside the field again, not up in the field’s border as these Material UI TextFields do then they are focused or have a current value. This is where I am hitting my roadblock. I have tried multiple solutions I found online, like using the inputRef/useCallback method to change the values, but it didn’t seem to work…or maybe I misunderstood and did it wrong. I was also recommended to put my search values to state. As happens with state my searches are now always one render behind (I.E. , results matching ‘US’ for ‘USA’ , ‘USA’ for ‘USAF’, etc…). Then when I run the handleFilterReset function to set the filter values back to an empty string, nothing happens. I just want my search filter to work instantly (like it did before I moved the value to state [commented out]) and be able to be cleared, resetting the table back to its default display.
Can someone please help me figure this out? Suggestions are appreciated, but code snippets are much more helpful since I am really new to React and especially Material UI.
dataTable.js
const [inputValue, setInputValue] = useState('')
const [searchFn, setSearchFn,] = useState({ fn: items => { return items; } });
// Searching Data
const handleSearch = e => {
setInputValue(e.target.value) // value displayed in input field
let query = (e.target.value).toString().toLowerCase();
setSearchFn({
fn: items => {
if (query === "")
return items;
else
return items.filter(x =>
(x.tankName !== null && x.tankName.toLowerCase().includes(query)) ||
(x.dimensions !== null && x.dimensions.toLowerCase().includes(query))
)
}
})
}
// Clearing Filters
const handleFilterReset = () => {
setInputValue('');
setSearchFn({fn: items => {return items;}})
};
// Search and filter Inputs
<div>
<InputSearch
value={inputValue}
onChange={handleSearch}
/>
<Button
text="Reset"
onClick={handleFilterReset}
/>
</div>
InputSearch.js
export default function InputSearch(props) {
const { inputRef, name, value, error=null, onChange, ...other } = props;
return (
<TextField
label="Search..."
name={name}
value={value}
onChange={onChange}
{...other}
{...(error && {error:true, helperText:error})}
>
</TextField>
)
}
You need to pass the value to InputSearch
Heres an example:
https://codesandbox.io/s/morning-brook-durbvd?file=/demo.tsx
React has a pretty good introduction on its site.
https://reactjs.org/docs/components-and-props.html
The code has been updated with a solution to this issue. I created a display value for the input that I passed to state, which was set to a blank string when the reset is pressed as well as passing an unfiltered data set.
I have a textarea array with values that can be updated. The text values in the array are updated when text is entered into the textarea. The array can also be updated externally.
The problem is that Textarea doesn't want to update its values with setState() like regular text does.
export function GameActions({}) {
const [array, setArray] = useState<Type>([]);
const changeText = (id: number, text: any) => {
actions[id].text = text;
setActions(actions);
};
return {actions.map((action, index) => (<Textarea
defaultValue={action.text}
onChange={(e) =>
changeText(index, e.currentTarget.value)
}
/>))};
};
Provided actions is an array state property, it should be:
setActions((actions)=>{
return actions.map((act,i)=>{
if(i == id) {
act.text = text;
}
return act;
});
});
When a state property is updated using its previous value, the callback argument should be used.
Also, to update an element of a state array, map should be used, rather than the indexation operator [].
Please read this article, to learn how to update state arrays.
I am trying to change the state by selecting and deselecting the language option in the code below. So far I can update the state by adding a language, my problem is that, if I click on the same language again, I will add it another time to the array. Can anyone explain me how to add or remove the language from the array when clicked one more time?
export default function Dashboard(props) {
const [language, setLanguage] = useState('');
const handleLanguageChange = changeEvent => {
changeEvent.persist()
setLanguage(prevState => [...prevState, changeEvent.target.value])
};
}
It looks like your only issue is your logic in the place where you are handling update. Usage of hooks is correct
So first of all you need to set proper initial value. As you plan to store your languages in an array.
Second part is updating the array. So you can either find clicked language in the array and if it is exist - then use filter to set your new value or filter and compare length of existing array and new one.
const [language, setLanguage] = useState([]);
const handleLanguageChange = changeEvent => {
changeEvent.persist()
setLanguage(prevState => {
const lang = changeEvent.target.value;
if (prevState.includes(lang) {
return prevState.filter(el => el !== lang);
}
return [...prevState, lang]
})
};
You will need a good old check.
if (!languages.includes(changeEvent.target.value) {
// code to add the language
}
Check the selected value using find() method on language array if it returns undefined, then push into array. Rename the state variable as languages otherwise it's confusing (Naming convention standard).
const [languages, setLanguages] = useState('');
const handleLanguageChange = changeEvent => {
changeEvent.persist()
if (!languages.find(value => value == changeEvent.target.value)) {
setLanguages(prevState => [...prevState, changeEvent.target.value])
}
};
2 Things here
Instead of having
<option value="Deutsch">Deutsch</option>
<option value="Englisch">Englisch</option>
use an languages array of json so it bacomes easy for you to add them like
languages= [{value='Deutsch',name= 'Deutsch',...}]
2.setLanguage sa a direct value
setLanguage(changeEvent.target.value)
I'm beginner with React JS and I'm doing a test project to train my skills.
I have a list of farms being rendered on the screen. The user can click on the button to register a new farm or can click on the property to be able to edit the existing property.
In a single Dialog Modal I do both. The problem is when I try to edit the Input field, it is not working. It doesn't matter what I type and nothing happens.
That's my input field, I'm using TextField from React Material:
<TextField
id="farmer-name"
label="Farm Name"
value={propertyData.farmerName}
onChange={(event) =>
changeField("farmerName", propertyData.id, event.target.value)
}
className={classes.input}
InputProps={{
className: classes.inputContent
}}
InputLabelProps={{
className: classes.inputLabel
}}
/>
And here's my function that will be able update my data:
const changeField = (field, id, value) => {
const newPropertyData = { ...propertyData };
if (newPropertyData.id === id) {
newPropertyData.field = value;
}
};
Here's my code, I put in CodeSandBox: https://codesandbox.io/s/spring-breeze-xnv3r?file=/src/index.js
Screen of my application
Can someone help me to edit that´s values? Thanks
You should save state on change in text field
const changeField = (field, id, value) => {
const newPropertyData = { ...propertyData };
if (newPropertyData.id === id) {
// change field value for specific id
newPropertyData[field] = value;
}
// set updated field value into state to show on form
setPropertyData(newPropertyData);
};
You are not actually changing the propertyData stored in the useState hook.
Currently, there will be a new property added called field in the newPropertyData object. However, this variable is never used or stored and you probably don't want the value to be stored in the field property.
The shortest answer is to pass a function to the setPropertyData which will receive the previous value of propertyData.
The previous propertyData can be extended with a dynamic property by using the following syntax: [field]: value.
const changeField = (field, id, value) => {
if (propertyData.id === id) {
setPropertyData(data => ({ ...data, [field]: value }));
}
};
I have a React Native form that allows me to add an Input UI in the form, by clicking a button with this function. This allow me to generate it on the fly. The code for that is this.
addClick() {
this.setState(prevState => ({ values: [...prevState.values, ""] }));
console.log(this.values[0].name);
}
That part works well, but I'm having a problem extracting the data from the dynamic inputs, and add it to an array. So far I have tried this
setVal = value => {
const values = this.state.values[0];
if (values[0].name === "" || values[0].description === "") return;
[...this.state.values, value];
this.setState(values);
console.log(values);
};
How do I organize my states properly so that I can add as many inputs I need, and when I'm finished, I can update the state, and access the new data in my list component?
How do I update my state to the new Array? at the moment, this.state only shows the initial state set at the top.
I'm missing a few things
Please take a look at the full code sandbox HERE so you can see:
See...your created isssue is not so obvious we need to see where you call setVal() function but....
i think you will be more comfortable if you render your <input/> s directly from your state array, not from const x = [] variant. because it seems like you want a dynamic view and in such a cases you will need to bind your loop quantity from state. so:
this.state = {
x: [0,1,2,3,4]
}
and inside your render :
{this.state.x.map(x => {
return (
<TextInput
placeholder={`name${x}`}
value={values[x.toString()]}
handleBlur={() => handleBlur(x.toString())}
onChangeText={handleChange(x.toString())}
style={styles.input}
/>
);
})}