Public
Edited
May 31, 2023
2 forks
Importers
33 stars
Insert cell
Insert cell
dateMap = new Map([
[new Date(Date.UTC(2001, 0, 1)), "red"],
[new Date(Date.UTC(2001, 0, 1)), "green"] // distinct key!
])
Insert cell
dateMap.get(new Date(Date.UTC(2001, 0, 1))) // undefined!
Insert cell
Insert cell
{
const date1 = new Date(Date.UTC(2001, 0, 1));
const date2 = new Date(Date.UTC(2001, 0, 1));
return date1 === date2; // false!
}
Insert cell
Insert cell
numberMap = new Map([[978307200000, "red"]])
Insert cell
numberMap.get(978307200000)
Insert cell
numberMap.get(new Date(978307200000)) // oops!
Insert cell
Insert cell
map = new InternMap([
[new Date(Date.UTC(2001, 0, 1)), "red"],
[new Date(Date.UTC(2001, 0, 1)), "green"] // replaces previous entry
])
Insert cell
map.get(new Date(Date.UTC(2001, 0, 1)))
Insert cell
[...map.keys()]
Insert cell
Insert cell
map.get(978307200000) // this works too!
Insert cell
Insert cell
map2 = new InternMap([
[978307200000, "red"], // danger!
[new Date(Date.UTC(2001, 0, 1)), "blue"]
])
Insert cell
map2.get(new Date(Date.UTC(2001, 0, 1))) // this still works…
Insert cell
[...map2.keys()] // but the key isn’t a Date
Insert cell
Insert cell
map3 = new InternMap([
[["foo", "bar"], 1],
[["foo", "baz"], 2],
[["goo", "bee"], 3]
], JSON.stringify)
Insert cell
map3.get(["foo", "baz"])
Insert cell
Insert cell
set = new InternSet([
new Date(Date.UTC(2000, 0, 1)),
new Date(Date.UTC(2001, 0, 1)),
new Date(Date.UTC(2001, 0, 1))
])
Insert cell
InternMap = d3.InternMap
Insert cell
InternSet = d3.InternSet
Insert cell

One platform to build and deploy the best data apps

Experiment and prototype by building visualizations in live JavaScript notebooks. Collaborate with your team and decide which concepts to build out.
Use Observable Framework to build data apps locally. Use data loaders to build in any language or library, including Python, SQL, and R.
Seamlessly deploy to Observable. Test before you ship, use automatic deploy-on-commit, and ensure your projects are always up-to-date.
Learn more