javascript - How can I sort DOM elements triggering the least amount of reflow? -


i've got following example.

<div class="parent">   <div data-id="5"></div>   <div data-id="2"></div>   <div data-id="3"></div>   <div data-id="1"></div>   <div data-id="4"></div> </div>

if want order these div's in ascending order (1,2,3,4,5). loop , append div's in order parent div. mean always make 5 changes dom (regardless of order of div's), 1 each div.

you can use .insertbefore() method order div's correctly 2 changes!

5,2,3,1,4 insert 1 before 2 5,1,2,3,4 insert 5 behind 4 (using .insertbefore() , .nextsibling) 1,2,3,4,5

question 1 making 2 changes dom assume less reflow ocours, making '2 change' sorting action faster '5 change'sorting action. correct?

question 2 sort of method/algorithm able figure out insert 1 before 2 , 5 behind 4?

question 3 (bonus) 'optimized' algorithm still faster amount of items incease? range 10 - 100 - 1.000 - 10.000 - 100.000

maybe clarify: not searching way figure out order (1,2,3,4,5) in optimal way. @ point know order want compare order agains order of div's , figure out least amount of operations.

be more confident in browsers’ capabilities.

  1. browsers batch dom operations when performed in 1 single, synchronous execution of javascript sequence. exceptions occur when explicitely (and unknowingly) request reflow accessing dom properties/methods require dom up-to-date, e.g. innerwidth, offsettop, or getboundingclientrect. see rendering: repaint, reflow, restyle details.
    deleting dom nodes not necessary. add them newly created documentfragment, they’ll automatically removed current position in dom.

  2. browsers, more js engines, know , use smartest sorting algorithm. save specific cases, don’t need know inner mechanisms of sorting operation. use array.prototype.sort, provide custom function if necessary, , watch magic happen.


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