How to retrieve the value of a key in session storage? I want to test the value of a key in session storage in a condition but it returns a negative result yet the value "student " is the value of the "roles" key, here is a schema on the code.
this.$q.sessionStorage.set('current_user', infos)
this.$q.sessionStorage.set('fullname', fullname)
this.$q.sessionStorage.set('roles', roles)
const professorRole = sessionStorage.getItem("roles")
const studentRole = sessionStorage.getItem("roles")
//console.log("stu " + professorRole);
if (studentRole !== null && studentRole.indexOf(2) === "student") {
console.log('email exists');
} else {
console.log('email not ok');
}
You could use either of the methods
getKey (index) => String,null or getAllKeys () => Array
on this.$q.sessionStorage
to retrieve the value of a key in session storage
Example:
let keys = this.$q.sessionStorage.getAllKeys()
Related
I use react native through firebase database
I have a database creating products each product has a number
I want to take a number and compare it with the product number
And if there is then I want to get a product
the function its give me my correct name but where i use it on render its not found the variable (name)
getAllContact = async key => {
let barCodeData2 = this.props.navigation.state.params.barcodeData
let self = this;
let contactRef = firebase.database().ref()
contactRef.on("value", dataSnapsot => {
if (dataSnapsot.val()) {
let contactResult = Object.values(dataSnapsot.val())
let contactKey = Object.keys(dataSnapsot.val())
contactKey.forEach((value, key) => {
contactResult[key]["key"] = value
})
self.setState({
fname: contactResult.fname,
data: contactResult.sort((a, b) => {
var nameA = a.barcode
var nameB = barCodeData2
const name = a.fname
console.log(`${nameA} What numers issssssss`);
if (nameA == nameB) {
alert(`${name} ........`)
console.log(`${nameA == nameB}is Equqlqlqlql`);
return name
}
}),
})
}
})
}
render() {
let t=this.state.name
alert(`${t} how?`)// is give Not found
// let d = this.props.navigation.state.params.barcodeData
return (
)
}
When you try such a comparison query i.e.
let ref = firebase.firestore();
ref.collection('zoo')
.where("id", "==", myID)
.get()
.then((snapshot) => {
console.log(snap.empty); //this will denote if results are empty
snapshot.forEach(snap => {
console.log(snap.exists); //alternatively this will also tell you if it is empty
})
})
well what you can do is run query based on you product no and if there's a product you will a product if there's none you will get an empty array.
read firebase documentation on queries
https://firebase.google.com/docs/reference/js/firebase.database.Query
I try to update a table.
I do a first request to get all rows then I update this table with same data but passwords are crypted before update.
'use strict';
var sql = require('./db.js');
var crypto = require('crypto');
var Crypt = require('./encryption.js');
//Support object constructor
var Login = function(login){
this.login = login.login;
this.password = login.password;
};
sql.query("SELECT * FROM login WHERE Password IS NOT NULL OR Password != ''", function(err,res) {
if (err) {
console.log(err);
}
else {
console.log(res.length);
for (var i = 0; i < res.length ; i++) {
//console.log(res[i].Password);
//if (res[i].Password != '' ){
sql.query("UPDATE login SET Password = ? where id=?", [Crypt.encrypt(res[i].Password), i], fu
if (err){
console.log(err);
}else {
console.log(res2, 'ok');
}
}) //}
}
}
})
When I do update only some rows are updatted but not all. I want to do it on all rows.
the mistake was in the query. I was using the iterator as id but ids aren't orderded in the database. It was res[i].id instead of i in the query parameter
I'm trying to get information (true/false) from AsyncStorage in a function and create a string which is importent to fetch data in the next step. My problem is, the function is not finished until the string is required.
I tried many solutions from the internet like async function and await getItem or .done() or .then(), but none worked out for me.
//_getFetchData()
AsyncStorage.getAllKeys().then((result) => { //get all stored Keys
valuelength = result.length;
if (valuelength !== 0) {
for (let i = 0; i < valuelength; i++) {
if (result[i].includes("not") == false) { //get Keys without not
AsyncStorage.getItem(result[i]).then((resultvalue) => {
if (resultvalue === 'true') {
if (this.state.firstValue) {
this.state.channels = this.state.channels + "channel_id" + result[i];
console.log("channel: " + this.state.channels);
}
else {
this.state.channels = this.state.channels + "channel" + result[i];
}
}
});
}
return this.state.channels;
_fetchData() {
var channel = this._getFetchData();
console.log("channel required: " + channel);
}
The current behaviour is that the console displays first "channel required: " than "channel: channel_id0".
Aspects in your question are unclear:
You don't say when this.state.firstValue is set, and how that relates to what you are trying to accomplish.
You have a for-loop where you could be setting the same value multiple times.
You mutate the state rather than set it. This is not good, see this SO question for more on that.
There are somethings we can do to make your code easier to understand. Below I will show a possible refactor. Explaining what I am doing at each step. I am using async/await because it can lead to much tidier and easier to read code, rather than using promises where you can get lost in callbacks.
Get all the keys from AsyncStorage
Make sure that there is a value for all the keys.
Filter the keys so that we only include the ones that do not contain the string 'not'.
Use a Promise.all, this part is important as it basically gets all the values for each of the keys that we just found and puts them into an array called items
Each object in the items array has a key and a value property.
We then filter the items so that only the ones with a item.value === 'true' remain.
We then filter the items so that only the ones with a item.value !== 'true' remain. (this may be optional it is really dependent on what you want to do)
What do we return? You need to add that part.
Here is the refactor:
_getFetchData = async () => {
let allKeys = await AsyncStorage.getAllKeys(); // 1
if (allKeys.length) { // 2
let filteredKeys = allKeys.filter(key => !key.includes('not')); // 3
let items = await Promise.all(filteredKeys.map(async key => { // 4
let value = await AsyncStorage.getItem(key);
return { key, value }; // 5
}))
let filteredTrueItems = items.filter(item => items.value === 'true'); // 6
let filteredFalseItems = items.filter(item => items.value !== 'true'); // 7
// now you have two arrays one with the items that have the true values
// and one with the items that have the false values
// at this points you can decide what to return as it is not
// that clear from your question
// return the value that your want // 8
} else {
// return your default value if there are no keys // 8
}
}
You would call this function as follows:
_fetchData = async () => {
let channel = await this._getFetchData();
console.log("channel required: " + channel);
}
Although the above will work, it will not currently return a value as you haven't made it clear which value you wish to return. I would suggest you build upon the code that I have written here and update it so that it returns the values that you want.
Further reading
For further reading I would suggest these awesome articles by Michael Chan that discuss state
https://medium.learnreact.com/setstate-is-asynchronous-52ead919a3f0
https://medium.learnreact.com/setstate-takes-a-callback-1f71ad5d2296
https://medium.learnreact.com/setstate-takes-a-function-56eb940f84b6
I would also suggest taking some time to read up about async/await and promises
https://medium.com/#bluepnume/learn-about-promises-before-you-start-using-async-await-eb148164a9c8
And finally this article and SO question on Promise.all are quite good
https://www.taniarascia.com/promise-all-with-async-await/
Using async/await with a forEach loop
Try this instead. Async functions and Promises can be tricky to get right and can be difficult to debug but you're on the right track.
async _getFetchData() {
let channels = "";
let results = await AsyncStorage.getAllKeys();
results.forEach((result) => {
if (result.includes("not") === false) {
let item = await AsyncStorage.getItem(result);
if (item === 'true') {
console.log(`channel: ${result}`)
channels = `channel_id ${result}`;
}
}
});
return channels;
}
_fetchData() {
this._getFetchData().then((channels) => {
console.log(`channel required: ${channel}`);
});
}
what if you wrap the _getFetchData() in a Promise? This would enable you to use
var channel = this._getFetchData().then(console.log("channel required: " + channel));
Otherwise the console.log won't wait for the execution of the _getFetchData().
This is what the console.log is telling you. it just logs the string. the variable is added after the async operation is done.
UPDATE
I would try this:
//_getFetchData()
AsyncStorage.getAllKeys().then((result) => { //get all stored Keys
valuelength = result.length;
if (valuelength !== 0) {
for (let i = 0; i < valuelength; i++) {
if (result[i].includes("not") == false) { //get Keys without not
AsyncStorage.getItem(result[i]).then((resultvalue) => {
if (resultvalue === 'true') {
if (this.state.firstValue) {
this.state.channels = this.state.channels + "channel_id" + result[i];
console.log("channel: " + this.state.channels);
}
else {
this.state.channels = this.state.channels + "channel" + result[i];
}
}
});
}
return new Promise((resolve, reject) => {
this.state.channels !=== undefined ? resolve(this.state.channels) : reject(Error('error '));
}
_fetchData() {
var channel = this._getFetchData().then(console.log("channel required: " + channel));
}
maybe you must change the this.state.channels !=== undefined to an expression that's matches the default value of this.state.channels.
I need to check if user with passed email OR login already exists in database.
const userModel = new User();
const user = await userModel.findByLogin(req.body.email, req.body.login);
if (user) {
req.checkBody('email', 'Email already in use').custom(value => user.email === value ? Promise.reject('Email already in use') : value);
req.checkBody('login', 'Login already in use').custom(value => user.login === value ? Promise.reject('Login already in use') : value);
}
const errors = req.validationErrors();
findByLogin takes email and login and returns existing user or null. Email validation works as expected. But if I try to register user with unique email and existing login, it doesn't create any errors (errors is false).
I just messed up with asynchronous validation. I cannot use validationErrors in my case, so I changed it to getValidationResult and it works fine now. Here is the result:
const userModel = new User();
const user = await userModel.findByLogin(req.body.email, req.body.login)
if (user) {
req.checkBody('email', 'Email already in use').custom(value => user.email !== value ? value : Promise.reject('Email already in use')).withMessage('Email already in use');
req.checkBody('login', 'Login already in use').custom(value => user.login !== value ? value : Promise.reject('Login already in use'));
}
const errors = await req.getValidationResult();
I am using react native async storage it works good but in some cases, I have to set an expiration date for data and refresh my storage I checked
AsyncStorage documentation but there are no options to set expire after a specific time.
only available options are:-
AsyncStorage.removeItem
AsyncStorage really only handles storage and nothing beyond that.
If you want to set an expiration, just put a key in your data for access date and set it to new Date(). Then, when you pull data, do a date check on the expiration key based on when it should expire.
first, I am storing objects, not strings so my solution will be based on object case if anyone uses strings he can append expireAt the object key then he will extract expire date and compare it with the current date
my solution:-
/**
*
* #param urlAsKey
* #param expireInMinutes
* #returns {Promise.<*>}
*/
async getCachedUrlContent(urlAsKey, expireInMinutes = 60) {
let data = null;
await AsyncStorage.getItem(urlAsKey, async (err, value) => {
data = (JSON.parse(value));
// there is data in cache && cache is expired
if (data !== null && data['expireAt'] &&
new Date(data.expireAt) < (new Date())) {
//clear cache
AsyncStorage.removeItem(urlAsKey);
//update res to be null
data = null;
} else {
console.log('read data from cache ');
}
});
//update cache + set expire at date
if (data === null) {
console.log('cache new Date ');
//fetch data
data = fetch(urlAsKey).then((response) => response.json())
.then(apiRes => {
//set expire at
apiRes.expireAt = this.getExpireDate(expireInMinutes);
//stringify object
const objectToStore = JSON.stringify(apiRes);
//store object
AsyncStorage.setItem(urlAsKey, objectToStore);
console.log(apiRes.expireAt);
return apiRes;
});
}
return data;
},
/**
*
* #param expireInMinutes
* #returns {Date}
*/
getExpireDate(expireInMinutes) {
const now = new Date();
let expireTime = new Date(now);
expireTime.setMinutes(now.getMinutes() + expireInMinutes);
return expireTime;
}
You can use this also, improvement from Ahmed Farag Mostafa answers
import AsyncStorage from "#react-native-async-storage/async-storage";
export default class ExpireStorage {
static async getItem(key) {
let data = await AsyncStorage.getItem(key);
data = JSON.parse(data);
if (
data !== null &&
data.expireAt &&
new Date(data.expireAt) < new Date()
) {
await AsyncStorage.removeItem(key);
data = null;
}
return data?.value;
}
static async setItem(key, value, expireInMinutes) {
const data = { value };
if (expireInMinutes) {
const expireAt = this.getExpireDate(expireInMinutes);
data.expireAt = expireAt;
} else {
const expireAt = JSON.parse(await AsyncStorage.getItem(key))?.expireAt;
if (expireAt) {
data.expireAt = expireAt;
} else {
return;
}
}
const objectToStore = JSON.stringify(data);
return AsyncStorage.setItem(key, objectToStore);
}
static async removeItem(key) {
return AsyncStorage.removeItem(key);
}
static getExpireDate(expireInMinutes) {
const now = new Date();
const expireTime = new Date(now);
expireTime.setMinutes(now.getMinutes() + expireInMinutes);
return expireTime;
}
}