ES2019 FEATURES
what even are they?
TARA Z. MANICSIC
our agenda:
@tzmanics | #FrontZurich
-
itty bitty intro
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MINOR FEATURES
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MAJOR FEATURES
-
TEENY TINY ouTRO
tara z. manicsic:
-
developer Experience | Netlify
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google developer expert
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CO-STARTER OF CINCY NODESCHOOL
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mother of toshmagosh
@tzmanics
& NIKO
our agenda:
-
itty bitty intro
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MINOR FEATURES
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MAJOR FEATURES
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TEENY TINY ouTRO
ITTY BITTY INTRO
@tzmanics | #FrontZurich
origin story:
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ECMA INTErnational
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ECMASCRipt
@tzmanics | #FrontZurich
PITFALLS & Weakness:
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es4: abandoned
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es6years
@tzmanics | #FrontZurich
FROM THE ASHES:
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tc39: we're all fine
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small packages
@tzmanics | #FrontZurich
proposal process:
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stage 0: strawman
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STAGE 1: proposal
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STAGE 2: draft
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STAGE 3: candidate
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STAGE 4: finished
@tzmanics | #FrontZurich
our agenda:
-
itty bitty intro
-
MINOR FEATURES
-
MAJOR FEATURES
-
TEENY TINY ouTRO
MINOR FEATURES
@tzmanics | #FrontZurich
String.prototype.{trimStart,trimEnd}
Sebastian Markbåge
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akin to
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New alias for
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what is whitespace?
.trim
.trimLeft
let tooMuchSpace = ' I need space. ';
//" I need space. "
console.log(JSON.stringify(tooMuchSpace.trimEnd()));
// " I need space."
console.log(JSON.stringify(tooMuchSpace.trimStart()));
// "I need space. "
console.log(JSON.stringify(tooMuchSpace.trim()));
// "I need space."
compatability
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👍CHROME
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👍fIrefox
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👍Safari
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👎EDGE
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👍Node 10+
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👍iOS
Symbol.prototype.description
Michael Ficarra
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string parameter
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no more converting
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this is the getter
let mySymbol = Symbol('#FrontZurich is great');
console.log(mySymbol);
// Symbol(#FrontZurich is great)
console.log(mySymbol.description);
// #FrontZurich is great
compatability
-
👍CHROME
-
👍fIrefox
-
👍Safari
-
👎EDGE
-
👍Node 10+
-
👍iOS
optional catch binding
Michael Ficarra
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NO PARAM? NO PROBLEM!
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the most Talked about?
try {
throw new Error('I know that already');
} catch (e) {
logMyErrors(e);
}
// w optional catch binding
try {
throw new Error('I know that already');
} catch {
}
compatability
compatability
-
👍CHROME
-
👍fIrefox
-
👍Safari
-
👎EDGE
-
👍Node 10+
-
👍iOS
Array.prototype.sort()
required to be stable
Mathias Bynens
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ecmascript spec
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what is stable?
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cut to the quicksort
let sortA = [
{'name': 'a', 'age': 2 },
{'name': 'a', 'age': 1 },
{'name': 'c', 'age': 1 },
{'name': 'a', 'age': 3 },
{'name': 'b', 'age': 1 }
];
sorte.sort((a,b) => a.age - b.age);
// [
// {name: "a", age: 1}
// {name: "c", age: 1}
// {name: "b", age: 1}
// {name: "a", age: 2}
// {name: "a", age: 3}
// ]
our agenda:
-
itty bitty intro
-
MINOR FEATURES
-
MAJOR FEATURES
-
TEENY TINY ouTRO
MajOR FEATURES
@tzmanics | #FrontZurich
Array.prototype.{flat,flatMap}
Michael Ficarra, Brian Terlson & Mathias Bynens
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recursively concats
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basically
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but there's more to it
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#smooshgate
.map.flat
let nested = [1, 2, [3, 4, [5, 6]], 7];
// (4) [1, 2, Array(3), 7]
nested.flat();
// (6) [1, 2, 3, 4, Array(2), 7]
nested.flat(2);
// (7) [1, 2, 3, 4, 5, 6, 7]
let arr = [1, 2, 3, 4];
arr.map(x => [x * x]);
// [[1], [4], [9], [16]]
arr.flatMap(x => [x * x]);
// [1, 4, 9, 16]
compatability
compatability
-
👍CHROME
-
👍fIrefox
-
👍Safari
-
👎EDGE
-
👍Node 11+
-
👍iOS
Object.fromEntries
Darien Maillet Valentine
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list of key-value pairs to object
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Opposite of
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dr.axel _underscore magic
Object.entries
2ality.com
let obj = {
key1: 'value 1',
key2: 'value 2',
key3: true
};
let entries = Object.entries(obj);
// (3) [Array(2), Array(2), Array(2)]
// 0: (2) ["key1", "value 1"]
// 1: (2) ["key2", "value 2"]
// 2: (2) ["key3", true]
let fromEntries = Object.fromEntries(entries);
//{key1: "value 1", key2: "value 2", key3: true}
compatability
compatability
-
👍CHROME
-
👍fIrefox
-
👍Safari
-
👎EDGE
-
👍Node 12
-
👍iOS
Well-formed
Richard Gibson
JSON.stringify
Richard Gibson
Michael Ficarra
Function.prototype.toString
JSON superset
revision
the other ones:
our agenda:
-
itty bitty intro
-
MINOR FEATURES
-
MAJOR FEATURES
-
TEENY TINY ouTRO
teeny tiny outro
@tzmanics | #FrontZurich
@tzmanics | #FrontZurich
@tzmanics | #FrontZurich
@tzmanics | #FrontZurich
💛
Thank you, front conference!
💛
@tzmanics | #FrontZurich
deck
By Tara Z. Manicsic
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