when Archives - For each javascript

how to set state when change viewport react


import React, { useLayoutEffect, useState } from 'react';

function useWindowSize() {
  const [size, setSize] = useState([0, 0]);
  useLayoutEffect(() => {
    function updateSize() {
      setSize([window.innerWidth, window.innerHeight]);
    }
    window.addEventListener('resize', updateSize);
    updateSize();
    return () => window.removeEventListener('resize', updateSize);
  }, []);
  return size;
}

function ShowWindowDimensions(props) {
  const [width, height] = useWindowSize();
  return <span>Window size: {width} x {height}</span>;
}

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how to show a success message when ajax called successfully


 BY LOVE,
 1- "beforeSend" event used to execute something before ajax call
 2- "complete"   event used to execute something after the ajax called successfull.
 
$.ajax({
                url: ' @Url.Action("AttendanceUpdateLate", "Attendance")',
                data: { Emp: $("#txtEmpid").val(), Status: $("#ddlAttendance").val(), day: $("#ddlday").val(), Month: $("#Month").val() },
                datatype: "json",
                type: "POST",
                contenttype: 'application/json; charset=utf-8',
                async: true,
                success: function (data) {
                    alert(data);
                },
                beforeSend: function () {
                    alert("Alert showing before AJAX call");

                },
                complete: function () {
                  alert("Alert showing after AJAX call successfully");
                    $("#txtEmpid").val('');
                    $("#ddlday").val('');
                    $("#ddlAttendance").val('');
                },
                error: function (xhr) {
                    alert('error occured');
                }
            });

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how to return when child process is complete in node js


var child = require('child_process').exec('python celulas.py')
child.stdout.pipe(process.stdout)
child.on('exit', function() {
  process.exit()
})


var execSync = require('exec-sync');

var user = execSync('python celulas.py');

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how to replace all the string in javascript when the string is javascript variable


const p = 'dog dog cat rat';

const regex = /dog/gi;

console.log(p.replace(regex, 'cow'));
//if pattern is regular expression all matches will be replaced
//output: "cow cow cat rat"


function name(str,replaceWhat,replaceTo){
    replaceWhat = replaceWhat.replace(/[-/\^$*+?.()|[]{}]/g, '\$&');
    var re = new RegExp(replaceWhat, 'g');
    return str.replace(re,replaceTo);
}


function name(str,replaceWhat,replaceTo){
    var re = new RegExp(replaceWhat, 'g');
    return str.replace(re,replaceTo);
}

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how to rerender a page in React when the user clicks the back button


We had a similar desire and solved it by passing a refresh function from the parent to the child.

for example, when you open the child, you would have something like navigate('Child', { refresh: refreshFunction }

You can then access this function in the child ( via something like this.props.navigation.state.params.refresh(); ) before the back action.