I have an Immutable.js collection that looks like this:
{ groups: Immutable.Map({
{
id: 1,
members: Immutable.List
},{
id: 2,
members: Immutable.List
}
})
}
I'm getting an updated members array and the group id from my server. How can I find the correct group by id and then update the members prop and then return a new groups collection?
I have something like this so far that doesn't work.
return state.update('groups', groups => {
for (let group of groups) {
if (group.id === action.id) {
group.members = Immutable.fromJS(action.members);
// not sure what I would do with updated here
//const updated = group.members.set('members', action.members);
}
}
return groups;
};
Also, tried this and it doesn't seem to complete, because the console.log never fires.
let update = state.get('groups')
.find(group => group.id === action.id)
.set('members', action.members)
console.log(update) // nothing, no error either
The following works, but there has to be a better, more elegant way than using fromJS and then toJS.
return state.update('groups', groupsImmutable => {
const groups = groupsImmutable.toJS();
for (let group of groups) {
if (group.id === activeId) {
group.members = action.members;
break;
}
}
return Immutable.fromJS(groups);
});
thanks!
This would work:
return state.update('groups', groups => {
return groups.map(group => {
if (group.get('id') === action.id) {
return group.set('members', Immutable.fromJS(action.members))
} else {
return group
}
})
})
You could also use findIndex to get the index of the matching group id and then use setIn to update the members array:
const updateIndex = state.get('groups').findIndex(group => group.get('id') === action.id);
if (updateIndex === -1) { // action.id not found
return state;
} else {
return state.setIn(['groups',updateIndex,'members'], Immutable.fromJS(action.members))
}
Your examples failed because you were trying to directly modify a child element, that's not how Immutable works. You need to update the entire state object with the new element.
Related
I have an array of object, I want to add key in my specifi object of array when Id is matched. I have tried this:
this.data.forEach(value => {
if (value.Id === attachmentDataId) {
AttachmentTypeId: this.attachmentRecord.AttachmentType;
}
});
But it's not working and it's not giving any error also
Try this out :
let data = [{ id: 1 }, { id: 5 }];
const attachmentDataId = 5;
const attachmentRecord = { AttachmentType: "AttachmentType" };
data.forEach(value => {
if (value.id === attachmentDataId) {
value.AttachmentTypeId = attachmentRecord.AttachmentType;
}
});
The stackblitz example: https://stackblitz.com/edit/js-nrhouh
You could use the index parameter of forEach function to access the specific object of the array.
this.data.forEach((value, i) => {
if (value.Id === attachmentDataId) {
this.data[i] = {
...this.data[i],
AttachmentTypeId: this.attachmentRecord.AttachmentType
};
}
});
Inside the if block, you could also instead do
this.data[i]['AttachmentTypeId'] = this.attachmentRecord.AttachmentType;
I just find using the spread operator cleaner.
use javascript map() method.
Map() return a new array, it takes a callback, iterates on each element in that array
const updatedData = data.map(res => {
if(res.id === attachmentDataId) {
res.AttachmentTypeId = attachmentRecord.AttachmentType;
}
return res
})
I need to push to the array cities if there is no such a city
getCityList() {
const { StoreInfo } = this.props;
this.emptyCityList();
return StoreInfo.map((StoreInfo, index) => {
console.log(this.cityPushCheck(StoreInfo.city));
if (this.cityPushCheck(StoreInfo.city)) {
CITY_LIST.push({
id: index, label: StoreInfo.city, value: StoreInfo.city, disabled: false
});
}
});
}
cityPushCheck(city) {
const MAP = CITY_LIST.map((CITY_LIST) => {
if (CITY_LIST.label === city) {
console.log('are equal');
return false;
}
});
return true;
}
I was trying return CITY_LIST.map((CITY_LIST) =>
without const or return CITY_LITS.map is not working
can't get it.
what I am doing wrong?
[UPDATE]
So this solution worked for me
getCityList() {
const { StoreInfo } = this.props;
this.emptyCityList();
return StoreInfo.map((StoreInfo, index) => {
if (this.cityPushCheck(StoreInfo.city)) {
CITY_LIST.push({
id: index, label: StoreInfo.city, value: StoreInfo.city, disabled: false
});
}
});
}
cityPushCheck(cityLabel) {
const cityFromList = CITY_LIST.find(city => city.label === cityLabel);
return cityFromList === undefined;
}
thanks to #quittle
It's a bit unclear what you are asking for exactly but I believe your question is how to implement cityPushCheck so that it returns false if the city is in CITY_LIST and true otherwise. Assuming CITY_LIST is an Array, there's a helpful function called find on arrays that greedily check for the presence of an entry based on a condition.
cityPushCheck(cityLabel) {
// Grabs the instance of the city from the list if it was present
const cityFromList = CITY_LIST.find(city => city.label === cityLabel);
// cityFromList will be undefined if "find" didn't have a match
return cityFromList === undefined;
}
While use map, you go city by city in your array, and for each return boolean. You might consider use filter, and then check if the filtered array have any length just once
cityPushCheck(city) {
CITY_LIST.filter(CITY => CITY.label == city).length
}
Now, if there isn't such city at array, length is 0 what is equal to false at JS
i'm having hard time figure out this. Have component which is search filter and pushes all selected filters into url. Everything works like it should except in case of refresh, in that case reducer is updated for selected filter with array with single item in which i have all selected items, not spreaded into array.
f.e. i have url
myexampleapp.com/alltrips?tripType=short_walk,cycling,downhill_cycling,long_walks&season=spring,summer,alle,vinter&lengthTo=50
my reducer
// ------------------------------------
// Constants
// ------------------------------------
export const UPDATE_FILTERS = 'UPDATE_FILTERS';
// ------------------------------------
// Actions
// ------------------------------------
const updateFilter = (key, value) => ({
type: UPDATE_FILTERS,
payload: {
key,
value
}
});
// ------------------------------------
// Action creators
// ------------------------------------
export const updateFilterState = (key, value) => {
return dispatch => {
dispatch(updateFilter(key, value));
};
};
// ------------------------------------
// Reducer
// ------------------------------------
const initialState = {
tripType: [],
season: [],
tripsTo: undefined,
tripsFrom: undefined
};
export function filterReducer (state = initialState, action) {
switch (action.type) {
case UPDATE_FILTERS: {
const key = action.payload.key;
const value = action.payload.value;
if (key === 'tripsFrom' || key === 'tripsTo') {
return Object.assign({}, state, { [key]: value });
} else {
var newFilter = state[key].slice();
var ttIdx = state[key].indexOf(value);
if (ttIdx !== -1) {
newFilter.splice(ttIdx, 1);
} else {
newFilter.push(value);
}
}
console.log(newFilter);
return Object.assign({}, state, { [key]: newFilter });
}
default:
return state;
}
}
console.log returns array with 1 element in which have array with 5 elements. but i want that 5 ekements to be in parrent array.
and i'm parsing URL
componentDidMount () {
let {
location: { search },
updateFilterState
} = this.props;
search = search.slice(1);
var queries = search.split('&');
queries.forEach(q => {
var tmp = q.split('=');
if (tmp[0] && tmp[1]) {
if (tmp[0].toLowerCase() === 'triptype') {
updateFilterState(tmp[0], tmp[1].split(','));
console.log(tmp[1].split(','));
} else if (tmp[0].toLowerCase() === 'tripsto') {
updateFilterState(tmp[0], tmp[1]);
} else if (tmp[0].toLowerCase() === 'tripsfrom') {
updateFilterState(tmp[0], tmp[1]);
} else if (tmp[0].toLowerCase() === 'season') {
updateFilterState(tmp[0], tmp[1].split(','));
}
}
});
this.updateQuery(this.props);
}
So everything works except when i want to refresh.
Pretty new with all this, and been stuck for almost 3 days with this. Hope you understand what im trying to ask here as i'm pretty new and non-english speaker, so i don't know all the terms so i can better express myself. Can someone give me some pointers?
If I'm not mistaken you are feeding the reducer with an array for season and tripType. So, when you try to update those values, you are not actually spreading that array. This is your value parameter. Hence, if you do this you will have a parent array with your desired result:
newFilter.push(...value);
... is ES6's spread syntax. So we are spreading our array and pushing it into our newFilter.
But again if I don't see it wrong you will have problems with this code since you are not checking the existence of your values right. You are looking indexOf something but if you really feeding your reducer with an array, for which one you are looking this index?
Here is a cleaner way of doing this if I'm not mistaken what you are trying to do here:
export function filterReducer (state = initialState, action) {
switch (action.type) {
case UPDATE_FILTERS: {
const { key, value } = action.payload;
if (key === 'tripsFrom' || key === 'tripsTo') {
return { ...state, [key]: value };
}
const newFilter = Array.isArray(value)
? [ ...new Set( [ ...state[key], ...value ] ) ]
: [ ...new Set( [ ...state[key], value ] ) ];
return { ...state, [key]: newFilter};
}
default:
return state;
}
}
Some differences with your code:
I am using spread syntax instead of Object.assign.
Instead of checking all the existence values (iterating the array and doing some logic) I'm using here Set object. It creates an object of unique values of what we give it. So I am cheating here and spreading our old state with spreading our value into an array, give this to our Set, and again at the top level spreading it again into an array. If you don't do the last spread you will get an object but here we want an array.
I'm new to react and as well to the terms of functional, imperative, declarative. And I get to know that pure function is easy to test. I am self taught to program with Javascript. So far, it is working but my goal is to learn to write clean and maintainable code.
my question is the method addProductToSaleList below is bad and untestable because it is imperative? and how can I do it differently.
class SaleComponent extends React.Component {
addProductToSaleList = (values, dispatch, props) => {
//filter product from productList
const productFound = props.productList.filter(product => {
if (values.productCode === product.code.toString()) {
return product
}
return undefined
})[0]
if (productFound) {
// filter sale list to check if there is already product in the list.
const detailFound = props.saleItem.details.filter(detail => {
if (productFound.name === detail.product) {
return detail
}
return undefined
})[0]
// if it is exist just increment the qty
if (detailFound) {
const { sub_total, ...rest } = detailFound
props.dispatcher('UPDATE_SALEDETAIL_ASYNC', {
...rest,
qty: parseInt(detailFound.qty, 10) + 1
})
// if it is not exist add new one
} else {
props.dispatcher('ADD_SALEDETAIL_ASYNC', {
product: productFound.id,
price: productFound.price,
qty: 1
})
}
} else {
alert('The product code you add is not exist in product list');
}
}
render() {
// Render saleList
}
}
I belive this question should go to Code Review, but I will give it a shot. Part of the code can be improved
const productFound = props.productList.filter(product => {
if (values.productCode === product.code.toString()) {
return product
}
return undefined
})[0]
First, filter function receives a callback and for each item that callback will be executed. If the callback returns a value interpreted as true, it will return the item in the new array the function will build. Otherwise, it will skip that item. Assuming you're trying to find one item in the code, you could use the function find which will return you that element directly (no need for [0]), or undefined if that item is not found. So your code could be rewrite to
const productFound = props.productList.find(product => values.productCode === product.code.toString());
Note: No IE support.
Then, if the value was not found, you could just alert and do an early return. (You might also want to handle errors differently, with a better format than plain alert).
The code would look like
if (!productFound) {
alert('The product code you add is not exist in product list');
return;
}
// rest of the function
in order to find details, you can use find method as well
const detailFound = props.saleItem.details.find(detail => productFound.name === detail.product);
and then just call the rest of the code
// if it is exist just increment the qty
if (detailFound) {
const { sub_total, ...rest } = detailFound
props.dispatcher('UPDATE_SALEDETAIL_ASYNC', {
...rest,
qty: parseInt(detailFound.qty, 10) + 1
})
// if it is not exist add new one
} else {
props.dispatcher('ADD_SALEDETAIL_ASYNC', {
product: productFound.id,
price: productFound.price,
qty: 1
})
}
Another improvement:
You're receiving a dispatch function as a parameter, but you're not using it. So you could remove it from function's declaration
(values, props) => { ... }
And you could split the last part into two different functions, something like
const getAction = details => `${detailFound ? 'UPDATE' : 'ADD'}_SALEDETAIL_ASYNC`;
const getObject = (details, productFound) => {
if (!details) {
return {
product: productFound.id,
price: productFound.price,
qty: 1
};
}
const { sub_total, ...rest } = detailFound;
return {
...rest,
qty: parseInt(detailFound.qty, 10) + 1
};
}
and then just call
props.dispatcher(getAction(details), getObject(details, productFound));
The end result would look like
addProductToSaleList = (values, props) => {
//filter product from productList
const productFound = props.productList.find(product => values.productCode === product.code.toString());
if (!productFound) {
alert('The product code you add is not exist in product list');
return;
}
// filter sale list to check if there is already product in the list.
const detailFound = props.saleItem.details.find(detail => productFound.name === detail.product);
const getAction = details => `${details ? 'UPDATE' : 'ADD'}_SALEDETAIL_ASYNC`;
const getObject = (details, productFound) => {
if (!details) {
return {
product: productFound.id,
price: productFound.price,
qty: 1
};
}
const { sub_total, ...rest } = details;
return {
...rest,
qty: parseInt(details.qty, 10) + 1
};
}
props.dispatcher(getAction(details), getObject(details, productFound));
}
my question is the method addProductToSaleList below is bad and
untestable because it is imperative
Well your code is testable, there are no external dependencies. So you could pass mocked values and props and add unit tests to that. That means, passing a fake values and props (they are just plain js object) and make assertions over that.
For instance:
You could mock dispatcher function and given the fake values in productList and saleItem.details you could see if dispatcher is called with the proper values. You should test different combinations of that
Mock alert function (Again, I would use another UI approach) and verify it is called, and that no other code is called (asserting that your fake dispatcher is not called). Something like this:
let actionToAssert;
let objectToAssert;
let values = { productCode: 'somecode' };
let props = {
productList: // your item listm with id and price, name, etc,
saleItem: {
details: // your details array here
}
dispatcher: (action, newObject) => {
actionToAssert = action;
objectToAssert = newObject;
}
}
addProductToSaleList(values, props); // make here assertions over actionToAssert and objectToAssert
A React component is passed a state property, which is an object of objects:
{
things: {
1: {
name: 'fridge',
attributes: []
},
2: {
name: 'ashtray',
attributes: []
}
}
}
It is also passed (as a router parameter) a name. I want the component to find the matching object in the things object by comparing name values.
To do this I use the filter method:
Object.keys(this.props.things).filter((id) => {
if (this.props.things[id].name === this.props.match.params.name) console.log('found!');
return (this.props.things[id].name === this.props.match.params.name);
});
However this returns undefined. I know the condition works because of my test line (the console.log line), which logs found to the console. Why does the filter method return undefined?
Object.keys returns an array of keys (like maybe ["2"] in your case).
If you are interested in retrieving the matching object, then you really need Object.values. And if you are expecting one result, and not an array of them, then use find instead of filter:
Object.values(this.props.things).find((obj) => {
if (obj.name === this.props.match.params.name) console.log('found!');
return (obj.name === this.props.match.params.name);
});
Be sure to return that result if you use it within a function. Here is a snippet based on the fiddle you provided in comments:
var state = {
things: {
1: {
name: 'fridge',
attributes: []
},
2: {
name: 'ashtray',
attributes: []
}
}
};
var findThing = function(name) {
return Object.values(state.things).find((obj) => {
if (obj.name === name) console.log('found!');
return obj.name === name;
});
}
var result = findThing('fridge');
console.log(result);
You need to assign the result of filter to a object and you get the result as the [id]. You then need to get the object as this.props.things[id]
var data = {
things: {
1: {
name: 'fridge',
attributes: []
},
2: {
name: 'ashtray',
attributes: []
}
}
}
var name = 'fridge';
var newD = Object.keys(data.things).filter((id) => {
if (data.things[id].name === name) console.log('found!');
return (data.things[id].name === name);
});
console.log(data.things[newD]);