Loading video...

Video Failed to Load

There was a problem loading this video. This could be due to a temporary network issue or the video might be unavailable.

JavaScript Maps are super underrated. Keys of a map can be anything - including an object! Here I'm using the new groupBy proposed API to group array items into a Map or an Object →

Wes Bos

437,608 subscribers

240,399 views • 3 years ago •via X (Twitter)

Anya Rossi• Live Now

Private livecam show

11 Comments

Nick Taylor3 years ago

WeakMaps ftw as well!

Wes Bos3 years ago

Nothing better than something that cleans up

Paulo Reis3 years ago

I've been using the JavaScript Maps a lot, thanks for the teachings 💯

Wes Bos3 years ago

big fan!

zayenz 🐀3 years ago

Maps are great, but I really miss structural equality for the keys when they are objects, as that is so much more useful. Especially if the key is computed at lookup.

Wes Bos3 years ago

I agree, I wonder if we will ever get that in JS

Web-Dev-Codi3 years ago

YT comment: You should use a for loop for performance. Wes: I'm iterating over 3 things brotha. 🤣 This was hilarious

vovô ermitão3 years ago

except that it lacks a hashing function hook

Wes Bos3 years ago

@crudspecialist What would we use that for? Not snark, curious!

Rocky3 years ago

@wesbos where can we find this video or podcasts ? Really interested in it

Wes Bos3 years ago

This is it - I made it for twitter

Related Videos

The Abandoned Mall DLC is here, bringing you a new map and 38 items for the object dropper! Time to level up your tricks on XBOX and dominate the Mall! 📷

The Abandoned Mall DLC is here, bringing you a new map and 38 items for the object dropper! Time to level up your tricks on XBOX and dominate the Mall! 📷

Session: Skate Sim

25,314 views • 2 years ago

A living man can be enslaved and reduced to the historic condition of an object. But if he dies in refusing to be enslaved, he reaffirms the existence of another kind of human nature which refuses to be classified as an object. Albert Camus

A living man can be enslaved and reduced to the historic condition of an object. But if he dies in refusing to be enslaved, he reaffirms the existence of another kind of human nature which refuses to be classified as an object. Albert Camus

Charlie Veitch

336,674 views • 11 months ago

Control and render on the map in three dimensions with the power of WebGL and the Maps JavaScript API. ✨ ✈️ Check out this demo to see plans for a trip to London, including the flight, transportation, stay, and attractions, all in one interactive setting ➡️

Control and render on the map in three dimensions with the power of WebGL and the Maps JavaScript API. ✨ ✈️ Check out this demo to see plans for a trip to London, including the flight, transportation, stay, and attractions, all in one interactive setting ➡️

Google Maps Platform

71,349 views • 5 months ago

FFXIV players, Stream Deck might be your BiS. Map gear sets to dedicated keys, keep actions and items within reach, and pull up your map and menus in an instant. Which one are you setting up first? 👇

FFXIV players, Stream Deck might be your BiS. Map gear sets to dedicated keys, keep actions and items within reach, and pull up your map and menus in an instant. Which one are you setting up first? 👇

Elgato

468,597 views • 3 months ago

#WATCH | Delhi: On Israel authorities using an incorrect map of India, Israeli Ambassador to India, Reuven Azar, says "...I hope that this phenomenon won't continue, but it doesn't have anything to do with what we think about India's borders...Different authorities are releasing maps from time to time, and these maps are not accurate. We're making an effort now, we have asked all the agencies to stop using bad maps..."

#WATCH | Delhi: On Israel authorities using an incorrect map of India, Israeli Ambassador to India, Reuven Azar, says "...I hope that this phenomenon won't continue, but it doesn't have anything to do with what we think about India's borders...Different authorities are releasing maps from time to time, and these maps are not accurate. We're making an effort now, we have asked all the agencies to stop using bad maps..."

ANI

66,575 views • 1 year ago

As a bit of an extra feature, we've added support for the additional buttons on the New Nintendo 3DS! Shown here, the C-Stick can be used to look around on the world map. Other additional bonus features are planned.

As a bit of an extra feature, we've added support for the additional buttons on the New Nintendo 3DS! Shown here, the C-Stick can be used to look around on the world map. Other additional bonus features are planned.

Super Mario Bros. Next

93,865 views • 1 year ago

Few people realise the scale of the Himalayas because static maps are a bad way to convey topography. Fortunately, we can use interactive maps to explore topography. Here is an example using Pyvista.

Few people realise the scale of the Himalayas because static maps are a bad way to convey topography. Fortunately, we can use interactive maps to explore topography. Here is an example using Pyvista.

Python Maps

691,638 views • 1 year ago

AOC: All those maps were passed by the state legislatures. Virginia was an election of three million Americans. This court did not overturn a map, it overturned an election. It’s one thing for a court to check a legislature or an executive but the end-all and be-all of power in America should be the people.

AOC: All those maps were passed by the state legislatures. Virginia was an election of three million Americans. This court did not overturn a map, it overturned an election. It’s one thing for a court to check a legislature or an executive but the end-all and be-all of power in America should be the people.

Acyn

437,551 views • 3 months ago

bear 🐻 - use a compile block to process each part, instead of an hda. - make a large height map using a stamp node from one height map. #houdini

bear 🐻 - use a compile block to process each part, instead of an hda. - make a large height map using a stamp node from one height map. #houdini

tinybugbot

41,026 views • 1 year ago

The multi-part Crownfall event comes to an epic close with Act IV, "The Spires of Skywrath," including a new overworld map, three distinct quests, new sidequests and minigames, and the introduction of an all-new playable character.

The multi-part Crownfall event comes to an epic close with Act IV, "The Spires of Skywrath," including a new overworld map, three distinct quests, new sidequests and minigames, and the introduction of an all-new playable character.

DOTA 2

327,611 views • 1 year ago

CA politicians are announcing where they'll run on the Legislature's new map even though (1) the Legislature can't legally adopt a map and (2) Newsom's scheme to give them that power is losing badly in polls. I've never seen a group so confident they can rig an election.

CA politicians are announcing where they'll run on the Legislature's new map even though (1) the Legislature can't legally adopt a map and (2) Newsom's scheme to give them that power is losing badly in polls. I've never seen a group so confident they can rig an election.

Kevin Kiley

73,169 views • 1 year ago

Archimedes' principle used in rescuing an elephant fallen in a well. The rule says that any object partially or completely submerged in a fluid experiences an upward force equal in magnitude to the weight of the fluid displaced by the object.

Archimedes' principle used in rescuing an elephant fallen in a well. The rule says that any object partially or completely submerged in a fluid experiences an upward force equal in magnitude to the weight of the fluid displaced by the object.

Ramesh Pandey

3,741,901 views • 5 months ago

Full vid of Ichigo dragging out the opponent to another map in #SparkingZero Destination maps are linked together, can be repeated infinitely, and are all empty maps (so he never goes to city or world tournament) Other example below

Full vid of Ichigo dragging out the opponent to another map in #SparkingZero Destination maps are linked together, can be repeated infinitely, and are all empty maps (so he never goes to city or world tournament) Other example below

Nyoh972

585,552 views • 11 months ago

Here's a copy/paste prompt recipe and vid showing exactly how to ask an LLM for an interactive map with satellite/map layers + a georeferencer that lets you see how old maps correspond with modern geography. Today the computer can’t make good print maps (that's your hill to climb ) but it can, with five bucks and twenty minutes, make good interactive maps. No software/GIS knowledge necessary, you just need a few nouns and an LLM. Scroll to the bottom for the repo/live map if you want those. I'm using Claude Code as an extension in VS Code but you can use the Claude CLI, Cursor, whatever. 1) Let's grab an old cadastral map and see who owned big tracts of a city; I found this an 1854 map of Niagara Falls, NY I found in the Library of Congress: , grabbed the .jp2, saved as a jpg from photoshop. 2) Let's ask Claude Code for a map. You can see exactly what I did in the video but my prompt, sans simple "hey it's busted" debugging, is written out in the following paragraphs. I explain the map-specific nouns in brackets. You can likely dump this whole thing in your LLM window and it'll work; I'd try plan mode + skip permissions. THE PROMPT Make an interactive map with MapLibre GL JS [maplibre is a javascript mapping library, a FOSS version of Mapbox GL JS. This lets us display tiled map data and arbitrary images on the map] Add basemap toggles with Esri satellite, Carto Positron, and OSM [these map layers require no API keys for light usage; Carto Positron is a nice road map layer and OSM is ugly but comprehensive] Add a globe/mercator projection toggle [I think the globe looks better at low zooms] Add a layer panel on the left with visibility checkboxes and delete buttons. Add a search box on the map that flies to results, with deletable pin markers [Makes this easy to get to your area of interest] Include an interactive local georeferencer: drop a JPG, pick ground control points on a zoomable/pannable image viewer, place them on the map, watch it warp with a progress bar centered on the map. [The georeferencer uses math ("affine transform"??) to match points on the old map to points on the new map; generally you click road intersections on the old map, match them on the new map, repeat a dozen times and everything aligns] The georeferenced map overlay defaults to 25% opacity with a slider above the control point list. [I want it easy to see the underlying modern geography] Add Export/import control point buttons [this saves the control points as a JSON so you can save and reimport your work] Add a button to export the warped image as a GeoTIFF with a .prj [In case you want to add the georeferenced image to a real GIS program like QGIS] Look up all relevant docs before starting [Claude sometimes uses outdated stuff] Split everything into separate HTML/CSS/JS files [Claude tends to pile everything in index.html, which is hard to read] Use Optima font, base color #FEFAF6 [I just like this style] Let me test with a local server [it serves it on a simple server so you can nav your host to localhost:8000 and try it out] Log all errors [so you don't have to play telephone with the LLM describing what's busted] 3) Once your LLM finishes, test it out in your browser; if it doesn't work, ask the LLM to check logs. Repeat 'til functional. 4) After this works on your computer, you can show it to everyone by hosting it on GitHub: prompt with "write a README explaining what everything does, add it to a new GitHub repo, deploy using GitHub pages, gimme the live URL" Here's what Claude made for me, try it yourself: • Upload the JPG in the repo, which is linked below • "Add GCP" • Click somewhere recognizable on the old map, like the tip of an island or a road intersection • Click the matching point on the new map • Repeat til you have least 3x points • Hit "georeference" • You'll see the old map atop the new map; if you want a better fit, delete bad points or add a dozen new ones, hit georeference again, repeat Repo: Is this map robust? Human-maintainable? Elegant? Performant? Secure? No, but *your* personal web map need not be. It just needs to work for *your* narrow use case, because it’s *your* map.

Here's a copy/paste prompt recipe and vid showing exactly how to ask an LLM for an interactive map with satellite/map layers + a georeferencer that lets you see how old maps correspond with modern geography. Today the computer can’t make good print maps (that's your hill to climb ) but it can, with five bucks and twenty minutes, make good interactive maps. No software/GIS knowledge necessary, you just need a few nouns and an LLM. Scroll to the bottom for the repo/live map if you want those. I'm using Claude Code as an extension in VS Code but you can use the Claude CLI, Cursor, whatever. 1) Let's grab an old cadastral map and see who owned big tracts of a city; I found this an 1854 map of Niagara Falls, NY I found in the Library of Congress: , grabbed the .jp2, saved as a jpg from photoshop. 2) Let's ask Claude Code for a map. You can see exactly what I did in the video but my prompt, sans simple "hey it's busted" debugging, is written out in the following paragraphs. I explain the map-specific nouns in brackets. You can likely dump this whole thing in your LLM window and it'll work; I'd try plan mode + skip permissions. THE PROMPT Make an interactive map with MapLibre GL JS [maplibre is a javascript mapping library, a FOSS version of Mapbox GL JS. This lets us display tiled map data and arbitrary images on the map] Add basemap toggles with Esri satellite, Carto Positron, and OSM [these map layers require no API keys for light usage; Carto Positron is a nice road map layer and OSM is ugly but comprehensive] Add a globe/mercator projection toggle [I think the globe looks better at low zooms] Add a layer panel on the left with visibility checkboxes and delete buttons. Add a search box on the map that flies to results, with deletable pin markers [Makes this easy to get to your area of interest] Include an interactive local georeferencer: drop a JPG, pick ground control points on a zoomable/pannable image viewer, place them on the map, watch it warp with a progress bar centered on the map. [The georeferencer uses math ("affine transform"??) to match points on the old map to points on the new map; generally you click road intersections on the old map, match them on the new map, repeat a dozen times and everything aligns] The georeferenced map overlay defaults to 25% opacity with a slider above the control point list. [I want it easy to see the underlying modern geography] Add Export/import control point buttons [this saves the control points as a JSON so you can save and reimport your work] Add a button to export the warped image as a GeoTIFF with a .prj [In case you want to add the georeferenced image to a real GIS program like QGIS] Look up all relevant docs before starting [Claude sometimes uses outdated stuff] Split everything into separate HTML/CSS/JS files [Claude tends to pile everything in index.html, which is hard to read] Use Optima font, base color #FEFAF6 [I just like this style] Let me test with a local server [it serves it on a simple server so you can nav your host to localhost:8000 and try it out] Log all errors [so you don't have to play telephone with the LLM describing what's busted] 3) Once your LLM finishes, test it out in your browser; if it doesn't work, ask the LLM to check logs. Repeat 'til functional. 4) After this works on your computer, you can show it to everyone by hosting it on GitHub: prompt with "write a README explaining what everything does, add it to a new GitHub repo, deploy using GitHub pages, gimme the live URL" Here's what Claude made for me, try it yourself: • Upload the JPG in the repo, which is linked below • "Add GCP" • Click somewhere recognizable on the old map, like the tip of an island or a road intersection • Click the matching point on the new map • Repeat til you have least 3x points • Hit "georeference" • You'll see the old map atop the new map; if you want a better fit, delete bad points or add a dozen new ones, hit georeference again, repeat Repo: Is this map robust? Human-maintainable? Elegant? Performant? Secure? No, but your personal web map need not be. It just needs to work for your narrow use case, because it’s your map.

Evan Applegate

15,772 views • 5 months ago

While reading a sign in the Behind the Waterfall area in Super Mario 64 DS, moving the camera to the left reveals an object that can appear as a Snifit, a coin, a Bob-omb or even as a "Coin-omb" depending on the angle. Stepping away from the sign reveals the object never existed.

While reading a sign in the Behind the Waterfall area in Super Mario 64 DS, moving the camera to the left reveals an object that can appear as a Snifit, a coin, a Bob-omb or even as a "Coin-omb" depending on the angle. Stepping away from the sign reveals the object never existed.

Supper Mario Broth

248,095 views • 1 year ago

A mysterious object crashed in the Jabun region over Indonesia. If it were clearly a missile, a meteorite, or space debris, it would have fallen at an angle. The mysterious object fell vertically. This appears to be a UFO crash.

A mysterious object crashed in the Jabun region over Indonesia. If it were clearly a missile, a meteorite, or space debris, it would have fallen at an angle. The mysterious object fell vertically. This appears to be a UFO crash.

永倉盛照 nagakura moriteru

779,072 views • 4 months ago