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