destructuring in js

arrays

[x,...y] = [1,2,3,4,5,6]

[1, 2, 3, 4, 5, 6]

x

1

y

[2, 3, 4, 5, 6]

 objects

var x2 = {name:"herby",amount:23423,happy:true,getStatus:function(){return this.name + (this.happy?" is happy":" isnt happy" )  }}

/with renaming variable

var {name:newname, getStatus:getit} = x2;

console.log(newname); //herby

console.log(getStatus); // function etc

Calculated Column logic

lets say you have a date column date1
you can have logic as follows

if(columna = "hello",Today(),"")

this should really fail because "" is not a date
it doesn't fail, but access for example will come up with #error

 lets say I want to keep the null



if(columna = "hello",Today(),date1)

this fails because of circular logic

if(columna = "hello",Today(),null)
if(columna = "hello",Today(),blank)

these are also not correct syntax

if(columna = "hello",Today())

that works but updates the column with a 0 which SharePoint shows incredibly as a 0

calculated columns in sharepoint

calculated columns (misnomer? they are real columns) update upon insert and update of the row. now , if you update the formula, sharepoint will show the new result but the underlying data will still be based on the old formula (you can see this in access linked table for example). he data will only really change when you do an update on the row

template literals

for template literals use the back tick "`"

console.log(`this is the sum of 8 X 45 :${8 * 45}`)
var x = {name:"herbert"}
console.log(`this is his name:${x.name }`)

select all on multi line textbox

     private void hody_KeyDown(object sender, KeyEventArgs e)

        {

          

             TextBox txtBox = sender as TextBox;

             if (txtBox != null && txtBox.Multiline == true && e.Control == true && e.KeyCode == Keys.A)

                 txtBox.SelectAll();

        }

ctrl-c on treeview

   private void TV_KeyDown(object sender, KeyEventArgs e)

        {

            if (e.KeyData == (Keys.Control | Keys.C))

            {

                if (TV.SelectedNode != null)

                {

                    Clipboard.SetText(TV.SelectedNode.Text);

                }

                e.SuppressKeyPress = true;

            }

        }

Example of csom looping recursively through termstore

  private void addNodes(TreeNode treeNode,Term term,string source = "Root")

        {

            if (term.Terms.Count > 0)

            {

                foreach (Term t in term.Terms)

                {

                    TreeNode tn = new TreeNode(string.Format("{0}  - {1}", t.Name, t.Id.ToString()));

                    treeNode.Nodes.Add(tn);

                    status.Text = string.Format("{0}-{1}", source, t.Name);

                    Application.DoEvents();

                    context.Load(t.Terms);

                    context.ExecuteQuery();

                    if (t.Terms.Count > 0)

                    {

                        addNodes(tn, t, string.Format("{0}-{1}", source, t.Name));

                    }

                }

            }

        }

 //calling code here

   foreach (Term t in ts.Terms)

            {

                TreeNode tn = new TreeNode(string.Format("{0}  - {1}", t.Name,t.Id.ToString()));

                status.Text = t.Name;

                Application.DoEvents();

                    //tn.Nodes.Add(string.Format("{0}",t.Id.ToString()));

                if (Recursive.Checked && (item.Text.Length == 0 || t.Name.Equals(item.Text, StringComparison.OrdinalIgnoreCase )))

                {

                    context.Load(t.Terms);

                    context.ExecuteQuery();

                    if (t.Terms.Count > 0)

                    {

                        addNodes(tn, t, t.Name);

                    }

                }

               treeNode.Nodes.Add (tn);

            }

          

            TV.Nodes.Add(treeNode);

logging into sharepoint with csom

   #region SECURITY

           

            string userName = this.User.Text;//

            string userPassword = this.pwd.Text;//            if (!string.IsNullOrWhiteSpace(userName) && !string.IsNullOrWhiteSpace(userPassword))

            {

               SecureString securePassword = new SecureString();

                    for (int i = 0; i < userPassword.Length; i++)

                    {

                        securePassword.AppendChar(userPassword[i]);

                    }

                if (!this.windows.Checked)

                {

                    SharePointOnlineCredentials creds = new SharePointOnlineCredentials(userName, securePassword);

                    context.Credentials = creds;

                }

                else

                {

                    NetworkCredential creds = new NetworkCredential(userName, securePassword);

                    context.Credentials = creds;

                }

            }

            #endregion

Calculated columns in sharepoint opened in access

If you have a calculated column thus

=IF([Status] ="Completed", TODAY(),"")

and the column is of type date

this is no issue for share point , the column will be empty if Status <> Completed

BUT access will read this as #error (but I have seen sometimes it reading it as 12/30/1899 (min date) and I do not know when or how this happens)

if you try iserror function it will not return yes, rather #error

any other function (len etc) will do that also - return #error

if you explicitly calculate like this 

=IF([Status] ="Completed", TODAY(),0)


access will work fine

but then again share point will have 12/30/1899 

Classes

class SimpleDate {

    constructor(year, month, day) {

     

        this.dt = new Date(year, month, day);

        this._year = year;

        this._month = month;

        this._day = day;

    }

    addDays(nDays) {

        dt += nDays;

    }

    getDay() {

        return this._day;

    }

}

class ComplicatedDate extends SimpleDate {

    constructor(year, month, day,Hour, Minute) {

        debugger;

    super(year, month, day);

    this.dt.setHours(this.dt.getHours()+Hour);

    this.dt.setMinutes(this.dt.getMinutes()+Minute);

    }

}

c = new     ComplicatedDate(1977,12,19,2,45);

Simple Generator

function* generateId(){
var i  = 0 ;
while(true){yield i++  }
}


const gen = generateId();
console.log(gen.next().value)
 0
console.log(gen.next().value)
 1
console.log(gen.next().value)
 2
console.log(gen.next().value)
 3

Promises example in JS and JSOM

 function getListItemByID(listName, itemID) {
return new Promise(function(resolve, reject) {
//debugger;
context = SP.ClientContext.get_current();
        web = context.get_web();
        oList = web.get_lists().getByTitle(listName);

        var currentItem = oList.getItemById(itemID);

        context.load(currentItem);
        context.executeQueryAsync(
            function () {
                resolve(currentItem);
            },
            function (sender, args) {
                reject(args.get_message());
            }
        );
});
};


getListItemByID("Milestones",843)
.then(row=>getListItemByID("Process List",row.get_item("Process_x0020_ID")))
.then(row=>console.log(row.get_item("Process_x0020_Name")))
.catch(error=>console.error(error))

Sets in JS (and spread operator)

Constructor

s= new Set()

Set {}

Methods

s.add(45)

s.add(34)

Set {45, 34}

s.clear()

Set {}

Using the spread operator to convert a set to an array

let t = new Set([...s].filter(x=>x ==34))

t

Set {34}

using spread to concatenate sets

x = [s,t]

[Set, Set]//unspread

x=[...s,...t]

[45, 34, 34]//spread

Intersect

new Set([...s].filter(x=>t.has(x)))

Set {34}

difference

new Set([...s].filter(x=>!t.has(x)))

Set {45}

Mapping JS

Declare

const testMap = new Map()

set map

testMap.set(1,{name:"boris",cash:345});

testMap.set(2,{name:"tony",cash:45});

testMap.set(3,{name:"peter",cash:5});

Map {1 => Object {name: "boris", cash: 345}, 2 => Object {name: "tony", cash: 45}, 3 => Object {name: "peter", cash: 5}}

properties

testMap.size

3

testMap.has(2)

true

testMap.has(56)

false

methods

testMap.get(3).name

"peter"

for loop

//first item in array is key and second is value

for(let item of testMap){ console.log( item[1].cash)}//value

345

45

5

for(let item of testMap.keys()){ console.log( item)}

1

2

3

Array methods

Using splice to add items in any position

const arr = ['a','b','c','d']

x = arr.splice(2,0,'3')

x will be empty - []

arr will be ["a", "b", "3", "c", "d"]

Add to the beginning of array

arr.unshift(-13)

[-13, "a", "b", "3", "c", "d"]

remove 1^st item

arr.shift()

["a", "b", "3", "c", "d"]

For Each

var temp =””

arr.forEach(function (item) {

    if (isNaN(item)) {

        temp += item;

    }

});

temp = "abcd"

mapping

const test =[{name:"herby",cash:23},{name:"boris",cash:456} ]

const cash = test.map(x=>x.cash)

cash = [23, 456]

Every and Some

const test2 =[{name:"herby",cash:23,eyecolor:"brown"},{name:"boris",cash:456} ]

test2.some(x=>x.eyecolor)

true

test2.every(x=>x.eyecolor)

false

Find

returns 1^st item

const z = test2.find(x=>{return x.eyecolor === "brown"})

z    {name:"herby",cash:23,eyecolor:"brown"}

const w = test2.find(x=>{return x.cash  > 0})

w   {name:"herby",cash:23,eyecolor:"brown"}

to get multiple items as an array use:

Filter

const t = test2.filter(x=>{return x.cash  > 0})

sort

 ascending

test2.sort((x,z)=>x.cash -z.cash)

descending

test2.sort((x,z)=>z.cash -x.cash)

Aggregating

console.log(test2.reduce((a,c)=>a+=c.cash,0))

479

why is 32 bit x86

here

New Parameter Functionality in JS

1. New Parameter Functionality
   
   Rest Params
   
   function testParams( i , ...j){
   var total = 0;
   j.forEach( function(value, index) { total += value; });
   return Math.pow(total,i);
   }
   testParams(2,1,2,3,4)
   100
   
   Rest Params with Arrow Functions
   function testParams( i , ...j){
   var total = 0;
   j.forEach( value => total += value);
   return Math.pow(total,i);
   
   }
   testParams(2,1,2,3,4)
   100
   
   default Params
   
   function testDefault(i, power =2){
   return Math.pow(i,power );
   }
   
   testDefault(10)
   100
   testDefault(10,3)
   1000

access list boxes - stop selection

use Locked property


if you use the enabled property then the scrollbars wont work

const in js

1. new const feature
   
   in the past there was no real constants in js, everything could be overwritten (even sometimes keywords)
   in ECMAScript6 this has been alleviated
   
   const in JS means the object can be assigned once
   if you try this
   
   const i = 45
   i= 0
   console.log(I)
   
   
   this will fail
   SyntaxError: Identifier 'i' has already been declared
   
   with objects member can be assigned afterwards
   
   
   const obj2 = {}
   obj2.a ="gg"
   
   
   
   but subsequent
   obj2 = {}
   will fail
   
   even with const, the only way to have a readonly member of an object is
   
   var testobj = {};
   Object.defineProperty( testobj , "pseudoconst",
   {
   value: 3,
   
   writable: false,
   
   enumerable: true,
   
   configurable: true
   });
   
   testobj.pseudoconst
   3
   testobj.pseudoconst = 5//this wont raise an error but wont change the value either
   5
   testobj.pseudoconst
   3
   
   

let in js

1. as Douglas Crockford has said, the worst feature of JavaScript is global variables.
   This has been alleviated greatly by block scoped variables
   
   consider the following
   
   
   var test ="herman"
   
   {
   test ="boris";
   console.log(test)
   }
   console.log(test)
   
   or
   
   
   var test ="herman"
   
   {
   var test ="boris";
   console.log(test)
   }
   console.log(test)
   
   the result will be
   
   
   boris
   boris
   
   However, with the new let keyword
   
   var test ="herman"
   
   {
   let test ="boris";
   console.log(test)
   }
   console.log(test)
   
   the results are now
   boris
   herman