I currently have a user object, which has a currentRoom() method on it, which might sometimes not exist or return null.
If the currentRoom() method returns something, I then need to call a messages() method on that. If nothing is returned from either, I’d like to return a default empty array [].
I’d like to tackle this functionally using Ramda, so it’s neat and reusable. Currently, my (non Ramda) code looks like this:
const user = Users.findOne({ username: params.id })
const room = (user.currentRoom && user.currentRoom() || {})
const messages = (room.messages && room.messages() || [])
Some kind of logic I was thinking was to pass in the list of required methods, along with the default result if nothing comes out of it.
/* getMessages(defaultIfNull, methodsArray, object) */
getMessages([], ['currentRoom', 'messages'], user)
Basically something a bit similar to pathOr, but for methods on objects.
I guess I'd use the List monad like an Option:
const getRoom = user => "currentRoom" in user ? [user.currentRoom()] : [];
const getMessages = room => "messages" in room ? room.messages() : [];
const allTogether = R.compose(R.chain(getMessage), R.chain(getRoom), R.of);
console.log(allTogether(Users.findOne({ username: params.id })));
You can use a point-free solution using just Ramda. First, we define a withDefaults function which will set up currentRoom and messages methods in objects which these methods are undefined.
var withDefaults = R.pipe(
// if don't have `currentRom` add a
// `currentRom` function that returns an empty object
R.unless(
R.hasIn('currentRoom'),
R.assoc('currentRoom',
R.always({}))),
// if don't have `messages` add a
// `messages` function that returns an empty array
R.unless(
R.hasIn('messages'),
R.assoc('messages',
R.always([]))))
This function filters the object setting up methods if needed. Usage example.
var user = withDefaults(getById(id))
Next, define a getter functions to get rooms and messages from objects. invoker is the central piece of this snipet, it returns a function that invokes a method. See http://ramdajs.com/docs/#invoker
var getCurrentRoom = R.invoker(0, 'currentRoom')
var getMessages = R.invoker(0, 'messages')
Above code can be used as following.
var userWithRoom = withDefaults({
currentRoom : function () {
return {
number : '123'
}
}
})
var userWithMessages = withDefaults({
messages : function () {
return [
'get lunch'
]
}
})
var userWithAll = withDefaults({
currentRoom : function () {
return {
number : '123'
}
},
messages : function () {
return [
'get lunch'
]
}
})
var userWithNone = withDefaults({})
All together
var withDefaults = R.pipe(
R.unless(
R.hasIn('currentRoom'),
R.assoc('currentRoom',
R.always({}))),
R.unless(
R.hasIn('messages'),
R.assoc('messages',
R.always([]))))
var getCurrentRoom = R.invoker(0, 'currentRoom')
var getMessages = R.invoker(0, 'messages')
// examples
var userWithRoom = withDefaults({
currentRoom : function () {
return {
number : '123'
}
}
})
var userWithMessages = withDefaults({
messages : function () {
return [
'get lunch'
]
}
})
var userWithAll = withDefaults({
currentRoom : function () {
return {
number : '123'
}
},
messages : function () {
return [
'get lunch'
]
}
})
Now lets test above code using console.log to see if our solution works as expected
console.log(getCurrentRoom(userWithRoom))
console.log(getCurrentRoom(userWithMessages))
console.log(getCurrentRoom(userWithAll))
console.log(getCurrentRoom(userWithNone))
console.log('---')
console.log(getMessages(userWithRoom))
console.log(getMessages(userWithMessages))
console.log(getMessages(userWithAll))
console.log(getMessages(userWithNone))
The output should be:
{ number: '123' }
{}
{ number: '123' }
{}
---
[]
[ 'get lunch' ]
[ 'get lunch' ]
[]
Related
I'm not really sure how to explain so I will start with the output.
I need to return this:
{
replies:
[
{ type: 'text', content: 'one' }
{ type: 'text', content: 'two' }
{ type: 'text', content: 'three' }
],
conversation: {
memory
}
}
And I wanted to return that through in-line statement.
So I would like to call something like:
reply.addText('one').addText('two').addText('three').addConversation(memory)
Note that addText can be called infinite times while addConversation can be called only one time. Also conversation is optional, in that case, if conversation is absent the conversation object should not appear in the output.
To create a custom structured object use a constructor, say Reply.
To call instance methods on the return value of method calls, return the instance object from the method.
Choices to prevent multiple additions of conversation objects include throwing an error (as below) or perhaps logging a warning and simply not add additional objects after a first call to addConversation.
Write the code to implement the requirements.
For example using vanilla javascript:
function Reply() {
this.replies = [];
}
Reply.prototype.addText = function( content) {
this.replies.push( {type: "text", content: content});
return this;
}
Reply.prototype.addConversation = function( value) {
if( this.conversation) {
//throw new Error("Only one conversation allowed");
}
this.conversation = {conversation: value};
return this;
};
Reply.prototype.conversation = null;
// demo
var reply = new Reply();
reply.addText( "one").addText("two").addConversation("memory?");
console.log( JSON.stringify( reply, undefined," "));
(The console.log uses JSON stringify to avoid listing inherited methods)
A possible implementation is to create a builder as follows:
function create() {
const replies = []; // store all replies in this array
let conversation; // store the memory here
let hasAddConversationBeenCalled = false; // a state to check if addConversation was ever called
this.addText = function(content) {
// add a new reply to the array
replies.push({
type: 'text',
content
});
return this; // return the builder
};
this.addConversation = function(memory) {
if (!hasAddConversationBeenCalled) { // check if this was called before
// if not set the memory
conversation = {
memory
};
hasAddConversationBeenCalled = true; // set that the memory has been set
}
return this; // return the builder
}
this.build = function() {
const reply = {
replies
};
if (conversation) { // only if converstation was set
reply.conversation = conversation; // add it to the final reply object
}
return reply; // finally return the built respnse
}
return this; // return the new builder
}
You can then use it as follows:
const builder = create();
const reply = builder.addText('one').addText('two').addText('three').addConversation({}).build();
Here is a link to a codepen to play around with.
If you specifically want to add assemble this via multiple function calls, then the builder pattern is your best bet, as vader said in their comment.
However, if the goal is to simply create shorthand for concisely building these objects, it can be done using a function that takes the list of text as an array.
const buildObject = (textArray, memory) => {
return Object.assign(
{},
{
replies: textArray.map(x => {
return {
type: 'text',
value: x
}
})
},
memory ? {conversation: memory} : null
)
}
var memory = { };
//with memory
console.log(buildObject(['one', 'two', 'three'], memory ))
//without memory
console.log(buildObject(['one', 'two', 'three']));
Fiddle example: http://jsfiddle.net/ucxkd4g3/
I have a container that holds search bar inside a form element consisting of two inputs, from and to, and a button.
On my form submit function, I create an OBJECT called query and it equals to:
const query = {
from : this.state.from,
to : this.state.to
};
then I pass this query object as an argument to an action that have created :
this.props.fetchPlaces(query);
In my action.js inside my fetchPlaces I have :
var skypicker = {
flyFrom : query.flyFrom,
flyTo : query.toCity,
};
I want to be able to pass flyFrom and flyTo to an api that later returns flights from flyFrom to flyTo which return results as JSON!
ofcourse i have to parse them to the URl, but at the current state flyFrom and flyTo are undefined, Am I doing this currectly?
You're accessing properties that you haven't set. The names differ between query and skypicker.
Try creating skypicker like this:
var skypicker = {
flyFrom: query.from,
flyTo: query.to
};
It’s query.from and query.to but not query.flyFrom and query.toCity
Check right one below
var skypicker = {
flyFrom : query.from,
flyTo : query.to
};
I generally do this
request body:
let data = {};
data.firstName = this.state.firstName;
data.lastName = this.state.lastName;
data.email = this.state.email;
data.password = this.state.password;
data.sex = this.state.sex;
this.props.registerUser(data);
action call:
export function registerUser(data) {
return dispatch => {
dispatch(registerUserRequest());
return ajax.post(URL_PREFIX + '/auth/register/', data)
.then(res => {
dispatch(registerUserSuccess(res.data))
setTimeout(function(){
dispatch(push('/login'))
}, 2000)
})
.catch(errors => {
dispatch(registerUserError(errors))
})
}
}
Let me how to find a json in javascript.
Sample Json:
{
"Employees" : [
{
"userId":"rirani",
"jobTitleName":"Developer",
"preferredFullName":"Romin Irani",
"employeeCode":"E1",
"region":"CA",
"phoneNumber":"408-1234567",
"emailAddress":"romin.k.irani#gmail.com"
},
{
"userId":"nirani",
"jobTitleName":"Developer",
"preferredFullName":"Neil Irani",
"employeeCode":"E2",
"region":"CA",
"phoneNumber":"408-1111111",
"emailAddress":"neilrirani#gmail.com"
}
]
]
}
the above json i want find particular userId based on employeeCode,emailAddress ad PhoneNumber. currently i am doing like below
for(var i=0; i<json.length;i++){
if((employeeCode==code)&&(emailAddress ==email)&&(PhoneNumber==phone)){
//here i am getting userId
}
}
I want know if this is the correct way. If it is small json load it ok. but if it's large scale of data what i have to do.
You can simply use the map function on the Employee array:
var data = {
"Employees" : [
{
"userId":"rirani",
"jobTitleName":"Developer",
"preferredFullName":"Romin Irani",
"employeeCode":"E1",
"region":"CA",
"phoneNumber":"408-1234567",
"emailAddress":"romin.k.irani#gmail.com"
},
{
"userId":"nirani",
"jobTitleName":"Developer",
"preferredFullName":"Neil Irani",
"employeeCode":"E2",
"region":"CA",
"phoneNumber":"408-1111111",
"emailAddress":"neilrirani#gmail.com"
}
]
};
var code ='E2' , email ='neilrirani#gmail.com' , phone = '408-1111111', userId;
data.Employees.map(x=>{
if(x.employeeCode == code && x.phoneNumber == phone && x.emailAddress== email){
userId = x.userId;
}
});
console.log(userId);
You can use find method which accepts a callback provided function applied on every item in the array.
The find() method returns the value of the first element in the array
that satisfies the provided testing function. Otherwise undefined is
returned.
let emailAddress="neilrirani#gmail.com";
let phone="408-1111111";
let code="E2";
let Employees = [
{
"userId":"rirani",
"jobTitleName":"Developer",
"preferredFullName":"Romin Irani",
"employeeCode":"E1",
"region":"CA",
"phoneNumber":"408-1234567",
"emailAddress":"romin.k.irani#gmail.com"
},
{
"userId":"nirani",
"jobTitleName":"Developer",
"preferredFullName":"Neil Irani",
"employeeCode":"E2",
"region":"CA",
"phoneNumber":"408-1111111",
"emailAddress":"neilrirani#gmail.com"
}
];
let employee=Employees.find(function(employee){
return employee.emailAddress==emailAddress && employee.phoneNumber==phone && employee.employeeCode==code;
});
console.log(employee.userId);
I'm trying to write a JavaScript function that returns results of an Elasticsearch v5 query. I can't figure out where and how to include 'return' in this code. With the following, segmentSearch(id) returns a Promise object,{_45: 0, _81: 0, _65: null, _54: null}.
_65 holds an array of the correct hits, but I can't figure out how to parse it. The console.log(hits) produces that same array, but how can I return it from the function?
var elasticsearch = require('elasticsearch');
var client = new elasticsearch.Client({
host: 'localhost:9200',
log: 'trace'
});
segmentSearch = function(id){
var searchParams = {
index: 'myIndex',
type: 'segment',
body: {
query: {
nested : {
path : "properties",
query : {
match : {"properties.source" : id }
},
inner_hits : {}
}
}
}
}
return client.search(searchParams).then(function (resp) {
var hits = resp.hits.hits;
console.log('hits: ',hits)
return hits;
}, function (err) {
console.trace(err.message);
});
}
I would instanitate a new array outside of your client.search function in global scope and array.push your 'hits' Then access your newly filled array.
let newArr = [];
client.search(searchParams).then(function (resp) {
for(let i = 0; i < resp.hits.hits.length; i++){
newArr.push(resp.hits.hits[i]);
}
console.log('hits: ',newArr)
return newArr;
}, function (err) {
console.trace(err.message);
});
First of all, elasticsearch js client is working with Promise ( I think using callback is also possible).
Using Promise is a good way to handle asynchronous computation.
In your question, you have already done something with a promise:
var search = function(id)
{
var searchParams = { /** What your search is **/}
return client.search(searchParams)
}
This call is returning a Promise.
If we consider handleResponse as the function in your then
var handleResponse = function(resp)
{
var hits = resp.hits.hits;
console.log('hits: ',hits)
return hits; //You could send back result here if using node
}
In your code, handleResponse is called once the promise is fullfield. And in that code you are processing data. Don't forget you are in asynchronious, you need to keep working with promise to handle hits.
By the way, in your question, what you have done by using "then" is chaining Promise. It is normal to have Promise.
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Promise/then
Promise.prototype.then is returning a Promise.
var segmentSearch = function ( id )
{
return search
.then( handleResponse //here you got your hit )
.then( function ( hits )
{
console.log(hits) //and here you have done something with hits from search.
})
}
I neglected to post my fix, sorry about that. The sequence is to create searchParams, perform client.search(searchParams) which returns a Promise of hits, then process those hits:
segmentSearch = function(obj){
// retrieve all segments associated with a place,
// populate results <div>
let html = ''
var plKeys = Object.keys(obj)
var relevantProjects = []
for(let i = 0; i < plKeys.length; i++){
relevantProjects.push(obj[plKeys[i]][0])
var searchParams = {
index: 'myIndex',
type: 'segment',
body: {
query: {
nested : {
path : "properties",
query : {
match : {"properties.source" : id }
},
inner_hits : {}
}
}
}
}
client.search(searchParams).then(function (resp) {
return Promise.all(resp.hits.hits)
}).then(function(hitsArray){
...write html to a <div> using hits results
}
}
to begin with, I have a multilevel of entities as in
country unit ----> customer reporting group ----> customers
each country unit has different customer reporting groups and each of the later has different customers
in the code the variable names are
cu ----> crg ---> customer
this is represented in a multilevel object called menuData:
menuData = {
cu1: {
CRG3: {
Customer1: {},
Customer5: {}
},
CRG7: {
Customer3: {},
Customer2: {},
Customer7: {}
}
},
cu4: {
CRG1: {
Customer2: {},
Customer4: {}
},
CRG3: {
Customer4: {}
}
}
};
what I wanted to do is to construct unique id for each level in a multilevel objects as well as in for example the ids for the customer units will be the same
cu1 and cu2 and so on
for the customer reporting groups the ids will consist of the cu + the crg as in
cu1+crg4
for the customer:
cu1+crg4+customer6;
what I did is a function called getIds
var getIds = function(menuData) {
var ids = {};
for (cu in menuData) {
ids[cu] = cu;
for (crg in menuData[cu]) {
if (!(ids[cu] in ids)) {
ids[cu] = {};
ids[cu][crg] = ids[cu].concat(crg);
} else ids[cu][crg] = ids[cu].concat(crg);
for (customer in menuData[cu][crg]) {
if (!ids[cu][crg]) {
ids[cu][crg] = {};
ids[cu][crg][customer] = ids[cu][crg].concat(customer);
} else ids[cu][crg][customer] = ids[cu][crg].concat(customer);
}
}
}
console.log(ids);
return ids;
};
the error I got is
Cannot read property 'concat' of undefined
what I have tried is that, because it says that it's undefined, I try to define it if its not already defined as in
if (!(ids[cu] in ids)) {
ids[cu] = {};
ids[cu][crg] = ids[cu].concat(crg);
}
if its not defined, define it and insert the value, but if its defined, only assign the value
else ids[cu][crg] = ids[cu].concat (crg );
why do I get this error? and how to get the the ids in multilevel objects ?
edit, excpected output is
ids = {
"cu1": {
"cu1+CRG3": { "cu1+CRG3+Customer1":{}, "cu1+CRG3+Customer5":{} },
"cu1+CRG7": { "cu1+CRG7+Customer3":{}, "cu1+CRG7+Customer2":{}, "cu1+CRG7+Customer7":{} }
},
"cu4": {
"cu4+CRG1": { "cu4+CRG1+Customer2":{}, "cu4+CRG1+Customer4":{} },
"cu4+CRG3": { "cu4+CRG3+Customer4":{}}
}
}
The Problem with your Code is that you are using Objects to store your data and Objects don´t have the Method "concat" only Arrays have the "concat" Method. Your Object must look like these to work:
menuData = [
"cu1": [
"CRG3": [ "Customer1":{}, "Customer5":{} ],
"CRG7": [ "Customer3":{}, "Customer2":{}, "Customer7":{} ]
],
"cu4": [
"CRG1": [ "Customer2":{}, "Customer4":{} ],
"CRG3": [ "Customer4":{}]
]
]
Here´s a reference : MDN Array.concat()
What can be confusing in JS is that an Object Property can be accessed like an Array.
Update after Expected Output was added:
okay than i think concat is not the right solution for your Problem.
Try it with something like this:
var ids = {};
var menuData = {
cu1: {
CRG3: {
Customer1: {},
Customer5: {}
},
CRG7: {
Customer3: {},
Customer2: {},
Customer7: {}
}
},
cu4: {
CRG1: {
Customer2: {},
Customer4: {}
},
CRG3: {
Customer4: {}
}
}
};
for (propKeyLevel1 in menuData){
ids[propKeyLevel1] = {};
var propLevel1 = ids[propKeyLevel1];
for(propKeyLevel2 in menuData[propKeyLevel1]){
propLevel1[propKeyLevel1+"+"+propKeyLevel2] = {};
var propLevel2 = propLevel1[propKeyLevel1+"+"+propKeyLevel2];
for(propKeyLevel3 in menuData[propKeyLevel1][propKeyLevel2]){
propLevel2[propKeyLevel1+"+"+propKeyLevel2+"+"+propKeyLevel3] = {};
}
}
}
console.log(ids);
concat is a method for for a String or an Array, here you call it on an object hence the error.
What you're trying to do is a bit unclear to me, but maybe you could try that :
ids[cu][crg] = crg;
instead of :
ids[cu][crg] = ids[cu].concat (crg );
Because that's what you seem to be trying.
I’d try it this way:
function getIds(dataIn, idsIn) {
idsIn = idsIn || [];
var dataOut = {}, idOut;
for (var idIn in dataIn) {
idsOut = idsIn.concat([idIn]);
dataOut[idsOut.join('+')] = getIds(dataIn[idIn], idsOut);
}
return dataOut;
}
Perfect use case for a recursive function passing down an array (idsOut) of the ids of the previous layers to generate the intended object keys. Pretty straight forward.