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What forces layout / reflow

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.

Element

Box metrics

• elem.offsetLeft, elem.offsetTop, elem.offsetWidth, elem.offsetHeight, elem.offsetParent
• elem.clientLeft, elem.clientTop, elem.clientWidth, elem.clientHeight
• elem.getClientRects(), elem.getBoundingClientRect()

mLuby

"use strict"


// Redux
  const bindActionCreators = (actionCreator, dispatch) => args => dispatch(actionCreator(args))
  const createStore = reducer => { // (state -> action -> state) -> Store
    let state = null
    const subscribers = []
    const dispatch = action => {
      state = reducer(state, action)

mLuby

# where process has name thing1...
ps aux | grep [t]hing1 | awk '{print $2}' | xargs kill

mLuby

# in data2.js replace , with ,\n then dump into data.js
cat data2.js | sed -e 's/,/,\'$'\n/g' > data.js

mLuby

IFS=$'\n'; # change delimiter so it works on all but newline filenames

for file in $(find ./ -name '*.js');
do mv "${file}" "${file}x" # file%jsx removes jsx from end of file
done

for file in $(find ./ -name '*spec.jsx');
do mv "${file}" "${file/unit.spec.jsx/spec.js}" # file%jsx removes jsx from end of file
done

mLuby

BOB=true
echo $BOB
if $BOB; then
  BOB=false
  echo $BOB
fi

mLuby

# tag a specific commit
git tag v1.7.1 4e13624

# rename a tag
old="1.7.1"
new="v1.7.1"
echo "$old -> $new"
git tag $new $old
git tag -d $old # delete the old tag locally
git push origin :refs/tags/$old # delete the old tag on remote

mLuby

"use strict"
// race all promises once and resolve with the first resolved promise or reject with the last error.
function raceWithTimeout (promiseList) {
  const TIMEOUT = 50
  return Promise.race([
    ...promiseList.map(suppressReject), // if any resolve, resolve with that result.
    lastRejectionWithTimeout(promiseList, TIMEOUT) // if all reject, reject with last error; if timeout, reject with latest error.
  ])
}

mLuby

{
  "rules": { // And why they're best practice (alphabetized).
    "accessor-pairs": [2, {"getWithoutSet": true}], // omission is usually by mistake.
    "array-bracket-spacing": 2, // spaces can make arrays take up a lot of space, and concise code allows for more reading context.
    "array-callback-return": 2, // omission is usually by mistake.
    "arrow-body-style": [2, "as-needed"], // improves consistency and readability.
    // "arrow-parens": [2, "as-needed"], // allows for concise arrows while improving consistency.
    "arrow-spacing": 2, // improves consistency and readability.
    "block-scoped-var": 2, // can behave unexpectedly due to variable hoisting.
    "block-spacing": 2, // helps differentiate blocks (spaced) from objects (not spaced).

mLuby

const dedup = list => list.reduce((uniques, item) => uniques.concat(uniques.includes(item) ? [] : [item]), []) 
dedup(["a",2,"a",3,"b",2]) // ["a", 2, 3, "b"]