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How to skip undefined/missing values in key-value pairs

I'm trying to build a citation generator from json in an API with data about images, stored in key-value pairs. I can get the data to return to the screen, but it always includes undefined in the citation. Sample manifest returns undefined as the creator since that isn't listed in this particular record. How can I keep any undefined value from being returned? I've tried changing the forEach to map, filtering at allMetadata by string length, using if !== undefined at insertCitation, and versions of those in different spots in the code.
EDIT: updated to provide full code, including print to page
(function () {
'use strict';
const buildCitation = {
buildMetadataObject: async function (collAlias, itemID) {
let response = await fetch('/iiif/info/' + collAlias + '/' + itemID + '/manifest.json');
let data = await response.json()
let allMetadata = data.metadata
let citationData = {};
allMetadata.forEach(function (kvpair) {
if (kvpair.value == undefined) {
return false;
} else if (kvpair.label === 'Title') {
citationData.itemTitle = kvpair.value;
} else if (kvpair.label === 'Creator') {
citationData.itemCreator = kvpair.value;
} else if (kvpair.label === 'Repository') {
citationData.itemRepository = kvpair.value;
} else if (kvpair.label === 'Collection Name') {
citationData.itemCollection = kvpair.value;
} else if (kvpair.label === 'Owning Institution') {
citationData.itemOwning = kvpair.value;
} else if (kvpair.label === 'Date') {
citationData.itemDate = kvpair.value;
} else if (kvpair.label === 'Storage Location') {
citationData.itemStorage = kvpair.value;
}
return true;
});
return citationData;
},
insertCitation: function (data) {
var testTitle = data.itemTitle;
console.log(testTitle);
const itemCite = `Citation: "${data.itemTitle}," ${data.itemDate}, ${data.itemCreator}, ${data.itemCollection}, ${data.itemOwning}, ${data.itemStorage}, ${data.itemRepository}.`;
const citationContainer = document.createElement('div');
citationContainer.id = 'citation';
citationContainer.innerHTML = itemCite;
// CHANGED to innerHTML instead of innerText because you may want to format it at some point as HTML code.
if (testTitle) {
document.querySelector('.ItemView-itemViewContainer').appendChild(citationContainer);
}
}
}
document.addEventListener('cdm-item-page:ready', async function (e) {
const citationData = await buildCitation.buildMetadataObject(e.detail.collectionId, e.detail.itemId);
console.log({ citationData });
buildCitation.insertCitation(citationData);
});
document.addEventListener('cdm-item-page:update', async function (e) {
document.getElementById('citation').remove();
const citationData = await buildCitation.buildMetadataObject(e.detail.collectionId, e.detail.itemId);
console.log({ citationData });
buildCitation.insertCitation(citationData);
});
})();

I've simplified your program. The undefined is coming from the fact that there is no item with label Date
const mappings = {
Date: 'itemDate',
Title: 'itemTitle',
Creator: 'itemCreator',
Repository: 'itemRepository',
'Storage Location': 'itemStorage',
'Owning Institution': 'itemOwning',
'Collection Name': 'itemCollection',
}
async function buildMetadataObject(collAlias, itemID) {
let response = await fetch('https://teva.contentdm.oclc.org/iiif/info/p15138coll25/1421/manifest.json');
let data = await response.json()
return data.metadata.reduce(
(acc, { label, value }) => ({ ...acc, [ mappings[label] ]: value }),
{}
)
}
function insertCitation(data) {
var testTitle = data.itemTitle;
const fieldBlackList = ['itemTitle'];
const itemCite = `Citation: "${data.itemTitle}," ${
Object.values(mappings).reduce((acc, cur) => {
if (fieldBlackList.includes(cur)) return acc;
const value = data[cur];
return value ? [...acc, value] : acc
}, []).join(', ')
}.`;
console.log(itemCite);
}
//MAIN PROGRAM
(async() => {
const citationData = await buildMetadataObject();
insertCitation(citationData);
})()

How to delete a key/value inside value field with Dexie.js?

I have a row with value like this below:
{
"id": 1,
"token": "abcd"
}
How do I delete and save the value without "token" so it becomes this?
{
"id": 1
}
Do I need to first get the object, modify it then save back?

Maybe this will help you:
function patch(db, id, delta) {
return new Promise((resolve, reject) => {
const tx = db.transaction('mystore', 'readwrite');
tx.onerror = (event) => reject(event.target.error);
tx.oncomplete = () => resolve();
const store = tx.objectStore('mystore');
const request = store.get(id);
request.onsuccess = (event) => {
const object = event.target.result;
if (!object) {
reject(new Error(`No matching object for ${id}`));
return;
}
for (const prop in delta) {
if (typeof delta[prop] === 'undefined') {
delete object[prop];
} else {
object[prop] = delta[prop];
}
}
store.put(object);
};
});
}
async function dostuff() {
let db;
const id = 1;
const delta = {
token: undefined
};
try {
db = await connect();
await patch(db, id, delta);
} finally {
if (db) {
db.close();
}
}
}

Objects in array are empty when return statement is included in function

I have a function that I want to return the array of objects parsedContacts. With the return statement there, the console.log above it prints an array of empty objects. When I remove the return statement, each object has three properties as expected.
How can I return the parsedContacts and include the properties?
/* eslint-disable no-console */
/* eslint-disable no-unused-vars */
import { PermissionsAndroid } from 'react-native';
import Contacts from 'react-native-contacts';
export const getAndProcessPhoneContacts = async () => {
PermissionsAndroid.request(
PermissionsAndroid.PERMISSIONS.READ_CONTACTS,
{
'title': 'Contacts',
'message': 'Xxxxxxxx would like to view your contacts.'
}
)
const contacts = await getContacts();
const parsedContacts = parseContacts(contacts);
sortContacts(parsedContacts);
console.log(parsedContacts);
return parsedContacts; // this line needs to be removed for parsedContacts to have properties in the objects inside it.
}
const getContacts = () => {
return new Promise((resolve, reject) => {
Contacts.getAll((error, contacts) => {
contacts ? resolve(contacts) : reject(error)
})
})
}
const parseContacts = contacts => {
return contacts.map(contact => {
let parsedContact = {}
Object.keys(contact).forEach(key => {
switch (key) {
case 'givenName':
parsedContact.firstName = contact[key]
break
case 'familyName':
parsedContact.surname = contact[key]
break
case 'phoneNumbers':
parsedContact.phoneNumber = contact[key].length ? contact[key][0].number : ''
}
})
return parsedContact
})
}
const sortContacts = contacts => {
contacts.sort((a, b) => {
let contactA = a.firstName;
let contactB = b.firstName;
return (contactA < contactB) ? -1 : (contactA > contactB) ? 1 : 0;
});
}
Update
As requested in the comments below, here is the calling function of getAndProcessPhoneContacts. I know that this is ugly and needs refactoring, any advice on this gratefully accepted too!
async componentDidMount() {
ConnectyCube.init(...config)
try {
const accessToken = await getFirebaseToken();
if (accessToken) {
await authorizeConnectyCube(accessToken);
if (this.props.user.parsedContacts) {
const registeredUsers = await retrieveRegisteredUsers();
this.props.updateRegisteredContacts(registeredUsers);
Actions.Dashboard();
} else {
const parsedContacts = await getParsedContactsFromStorage();
if (parsedContacts) {
this.props.updateParsedContacts(parsedContacts);
Actions.Dashboard();
} else {
const parsedContacts = await getAndProcessPhoneContacts();
console.log(parsedContacts); // prints an array of empty objects
await writeParsedContactsToStorage(parsedContacts);
this.props.updateParsedContacts(parsedContacts);
const registeredUsers = await retrieveRegisteredUsers();
this.props.updateRegisteredContacts(registeredUsers);
Actions.Dashboard();
}
}
} else {
Actions.PhoneNumberInput();
}
} catch (error) {
Alert.alert(error);
}
}
Update 2
I have an inelegant solution by using a callback:
const cb = (ct) => {
console.log(ct); // Objects now have properties
}
const parsedContacts = await getAndProcessPhoneContacts(cb);
await writeParsedContactsToStorage(parsedContacts);
this.props.updateParsedContacts(parsedContacts);
const registeredUsers = await retrieveRegisteredUsers();
this.props.updateRegisteredContacts(registeredUsers);
Actions.Dashboard();
}
}
} else {
Actions.PhoneNumberInput();
}
} catch (error) {
Alert.alert(error);
}
}
And the called function:
export const getAndProcessPhoneContacts = async (cb) => {
PermissionsAndroid.request(
PermissionsAndroid.PERMISSIONS.READ_CONTACTS,
{
'title': 'Contacts',
'message': 'Xxxxxxx would like to view your contacts.'
}
)
const contacts = await getContacts();
const parsedContacts = parseContacts(contacts);
sortContacts(parsedContacts);
console.log(parsedContacts);
cb(parsedContacts)
}

javascript array filter very slow in REACT

I have a custom listbox, a div that contains a vertical list of other div children. And I have input for search something else in the list. It's working but in large data, it's working very slowly.
Also search criterion produce dynamically with column chooser. How can i increase search performance.
Firsly, prepare filter data for search and keeping state on the page load
prepareFilterData(allData) {
const filteredData = [];
let columnChooser = JSON.parse(getItemFromLocalStorage("ColumnData"));
allData.map(item => {
var data = "";
columnChooser.map(element => {
var newData = { value: item[element.value], format: element.format };
var filterItem = getFilterDataFormat(newData);
data += filterItem + " ";
});
filteredData.push(data);
});
this.setState({
filteredData: filteredData
});
}
Secondly, When user enter an char to textbox, i'm checking filteredData
filterList() {
const updatedList = this.state.allData.length > 0 ? this.state.allData : [];
var filteredData = [];
filteredData = updatedList.filter((item, index) => {
const data = this.state.filteredData[index];
return data.indexOf(this.state.searchInputValue) !== -1;
});
return filteredData;
}
This is input statement
<input
id="searchBox"
type="text"
className="filter-input empty"
placeholder="Search"
onChange={this.filterList}
value={this.props.state.searchInputValue}
style={{ width: "100%" }} />

Using a standard for loop can significantly increase the performance, especially in your case where you're using indexOf which is causing another iteration in your filter. The filter operation uses callbacks and it's often used because of the simpler syntax but it's these callback that make the operation to be slower especially on big data.
Read more here.

I found the solution.
SOLUTION:
I create a util.js in my project, and I called createFilter function.
import Fuse from "fuse.js";
import { toTrLowerCase } from "./process";
function flatten(array) {
return array.reduce((flat, toFlatten) => flat.concat(Array.isArray(toFlatten) ? flatten(toFlatten) : toFlatten), []);
}
export function getValuesForKey(key, item) {
const keys = key.split(".");
let results = [item];
keys.forEach(_key => {
const tmp = [];
results.forEach(result => {
if (result) {
if (result instanceof Array) {
const index = parseInt(_key, 10);
if (!isNaN(index)) {
return tmp.push(result[index]);
}
result.forEach(res => {
tmp.push(res[_key]);
});
} else if (result && typeof result.get === "function") {
tmp.push(result.get(_key));
} else {
tmp.push(result[_key]);
}
}
});
results = tmp;
});
// Support arrays and Immutable lists.
results = results.map(r => (r && r.push && r.toArray ? r.toArray() : r));
results = flatten(results);
return results.filter(r => typeof r === "string" || typeof r === "number");
}
export function searchStrings(strings, term, { caseSensitive, fuzzy, sortResults, exactMatch } = {}) {
strings = strings.map(e => e.toString());
try {
if (fuzzy) {
if (typeof strings.toJS === "function") {
strings = strings.toJS();
}
const fuse = new Fuse(
strings.map(s => {
return { id: s };
}),
{ keys: ["id"], id: "id", caseSensitive, shouldSort: sortResults }
);
return fuse.search(term).length;
}
return strings.some(value => {
try {
if (!caseSensitive) {
value = value.toLowerCase();
}
if (exactMatch) {
term = new RegExp("^" + term + "$", "i");
}
if (value && value.search(term) !== -1) {
return true;
}
return false;
} catch (e) {
return false;
}
});
} catch (e) {
return false;
}
}
export function createFilter(term, keys, options = { caseSensitive: false, fuzzy: false, sortResults: false, exactMatch: false }) {
debugger;
return item => {
if (term === "") {
return true;
}
if (!options.caseSensitive) {
term = term.toLowerCase();
}
const terms = term.split(" ");
if (!keys) {
return terms.every(term => searchStrings([item], term, options));
}
if (typeof keys === "string") {
keys = [keys];
}
return terms.every(term => {
// allow search in specific fields with the syntax `field:search`
let currentKeys;
if (term.indexOf(":") !== -1) {
const searchedField = term.split(":")[0];
term = term.split(":")[1];
currentKeys = keys.filter(key => key.toLowerCase().indexOf(searchedField) > -1);
} else {
currentKeys = keys;
}
return currentKeys.some(key => {
const values = getValuesForKey(key, item);
values[0] = toTrLowerCase(values[0]);
return searchStrings(values, term, options);
});
});
};
}
And then i added fuse.js to package.json.
"fuse.js": "^3.0.0"
I called createFilter function like that... term is searching value key
keysToFilter is which array column you wanna search.
this.state.allData.filter(createFilter(term, this.state.keysToFilter));
Link: https://github.com/enkidevs/react-search-input

How to wrap FileSystemFileEntry.file into a function that returns Observable?

I'm trying to read files recursively from the dropped folder.
onDrop(event) {
event.preventDefault();
this.folderData = [];
this.filesData = [];
const items = event.dataTransfer.items;
for (let i = 0; i < items.length; i++) {
const item = items[i].webkitGetAsEntry();
if (item) {
this.scanFiles(item, this.folderData);
}
}
// send out data
// this.dropped.emit({ folderData: this.folderData, filesData: this.filesData });
}
private scanFiles(item, container: Array<any>) {
const nodeData = {
name: item.name,
isDirectory: item.isDirectory,
item: item,
children: []
};
container.push(nodeData);
if (item.isDirectory) {
const directoryReader = item.createReader();
directoryReader.readEntries(entries => {
if (entries) {
entries.forEach(entry => this.scanFiles(entry, nodeData.children));
}
});
} else if (item.isFile) {
// How to return an Observable array here?
item.file(file => {
file.fullPath = item.fullPath;
this.filesData.push(file);
});
}
}
According to MDN, FileSystemFileEntry.file returns the result in its callback.
https://developer.mozilla.org/en-US/docs/Web/API/FileSystemFileEntry/file
So before onDrop sends out the result, it has to wait, until all the FileSystemFileEntry.file callbacks complete.
I want to use Observable.forkJoin to achieve this. But before that, how to wrap FileSystemFileEntry.file into a function that returns Observable?

It turns out that a single forkJoin can't resolve the problem. I finally complete this by recursive forkJoin.
onDrop(event) {
event.preventDefault();
this.folderData = [];
this.filesData = [];
const items = event.dataTransfer.items;
const obs = [];
for (let i = 0; i < items.length; i++) {
const item = items[i].webkitGetAsEntry();
if (item) {
obs.push(new Observable<any>(observer => this.scanFiles(item, this.folderData, observer)));
}
}
forkJoin(obs).subscribe(e => {
this.dropped.emit({ folderData: this.folderData, filesData: this.filesData });
});
}
private scanFiles(item, container: Array<any>, observer: Subscriber<any>) {
const nodeData = {
name: item.name,
isDirectory: item.isDirectory,
item: item,
children: []
};
container.push(nodeData);
if (item.isDirectory) {
const directoryReader = item.createReader();
directoryReader.readEntries(entries => {
if (entries) {
if (entries.length === 0) {
observer.next();
observer.complete();
} else {
const subObs = entries.map(entry => new Observable<any>(innerObserver =>
this.scanFiles(entry, nodeData.children, innerObserver)));
forkJoin(subObs).subscribe(e => {
observer.next();
observer.complete();
});
}
} else {
observer.next();
observer.complete();
}
});
} else if (item.isFile) {
item.file(file => {
file.fullPath = item.fullPath;
this.filesData.push(file);
observer.next();
observer.complete();
});
}
}
For more detial check https://github.com/ft115637850/ngx-folder-uploader.