| // Referred in - https://codeburst.io/throttling-and-debouncing-in-javascript-b01cad5c8edf | |
| // Start execute the function until, no more action request. Last requrest get performed. | |
| // Use case - Auto Save, Submit, file send action | |
| const debounce = (func, delay) => { | |
| let inDebounce | |
| return function() { | |
| const context = this | |
| const args = arguments | |
| clearTimeout(inDebounce) |
None of the string methods modify this – they always return fresh strings.
charAt(pos: number): string ES1
Returns the character at index pos, as a string (JavaScript does not have a datatype for characters). str[i] is equivalent to str.charAt(i) and more concise (caveat: may not work on old engines).
This content moved here: https://exploringjs.com/impatient-js/ch_arrays.html#quickref-arrays
This recipe is useful for cooking up chained API calls as a result of a single action.
In the below example, a single action called POST_REPO is dispatched and it's intention is to create a new repostiory on GitHub then update the README with new data after it is created.
For this to happen there are 4 API calls necessary to the GitHub API:
While attempting to explain JavaScript's reduce method on arrays, conceptually, I came up with the following - hopefully it's helpful; happy to tweak it if anyone has suggestions.
JavaScript Arrays have lots of built in methods on their prototype. Some of them mutate - ie, they change the underlying array in-place. Luckily, most of them do not - they instead return an entirely distinct array. Since arrays are conceptually a contiguous list of items, it helps code clarity and maintainability a lot to be able to operate on them in a "functional" way. (I'll also insist on referring to an array as a "list" - although in some languages, List is a native data type, in JS and this post, I'm referring to the concept. Everywhere I use the word "list" you can assume I'm talking about a JS Array) This means, to perform a single operation on the list as a whole ("atomically"), and to return a new list - thus making it much simpler to think about both the old list and the new one, what they contain, and
FWIW: I (@rondy) am not the creator of the content shared here, which is an excerpt from Edmond Lau's book. I simply copied and pasted it from another location and saved it as a personal note, before it gained popularity on news.ycombinator.com. Unfortunately, I cannot recall the exact origin of the original source, nor was I able to find the author's name, so I am can't provide the appropriate credits.
| function scrollTo(element, to, duration) { | |
| if (duration < 0) return; | |
| var difference = to - element.scrollTop; | |
| var perTick = difference / duration * 2; | |
| setTimeout(function() { | |
| element.scrollTop = element.scrollTop + perTick; | |
| scrollTo(element, to, duration - 2); | |
| }, 10); | |
| } |
By: @BTroncone
Also check out my lesson @ngrx/store in 10 minutes on egghead.io!
Update: Non-middleware examples have been updated to ngrx/store v2. More coming soon!
Table of Contents
All of the below properties or methods, when requested/called in JavaScript, will trigger the browser to synchronously calculate the style and layout*. This is also called reflow or layout thrashing, and is common performance bottleneck.
Generally, all APIs that synchronously provide layout metrics will trigger forced reflow / layout. Read on for additional cases and details.
elem.offsetLeft, elem.offsetTop, elem.offsetWidth, elem.offsetHeight, elem.offsetParent