Replace parquet-wasm + apache-arrow with hyparquet

The dataset's index parquets are tiny (~1–2 KB each) yet we were forcing
every cold visitor to download a 6.3 MB WASM blob plus an Apache Arrow
runtime to parse them. Swapped to hyparquet (pure-JS, ~30 KB, no init
step) and stripped both heavy deps. parquet.ts now wraps the fetched
ArrayBuffer as a synchronous AsyncBuffer; date columns surface as Date
from hyparquet so we just normalize them to ISO strings here.

First-paint payload before/after:
- parquet_wasm_bg.wasm: 6,300 KB -> 0 (file no longer emitted)
- apache-arrow chunk: ~140 KB -> 0
- hyparquet replacement: ~30 KB

bun.lock

@@ -5,9 +5,8 @@
     "": {
       "name": "app",
       "dependencies": {
-        "apache-arrow": "^21.1.0",
+        "hyparquet": "^1.25.6",
         "mediabunny": "^1.42.0",
-        "parquet-wasm": "^0.7.1",
       },
       "devDependencies": {
         "@fontsource-variable/oxanium": "^5.2.8",
@@ -185,10 +184,6 @@
 
     "@tybys/wasm-util": ["@tybys/wasm-util@0.10.1", "", { "dependencies": { "tslib": "2.8.1" } }, "sha512-9tTaPJLSiejZKx+Bmog4uSubteqTvFrVrURwkmHixBo0G4seD0zUxp98E1DzUBJxLQ3NPwXrGKDiVjwx/DpPsg=="],
 
-    "@types/command-line-args": ["@types/command-line-args@5.2.3", "", {}, "sha512-uv0aG6R0Y8WHZLTamZwtfsDLVRnOa+n+n5rEvFWL5Na5gZ8V2Teab/duDPFzIIIhs9qizDpcavCusCLJZu62Kw=="],
-
-    "@types/command-line-usage": ["@types/command-line-usage@5.0.4", "", {}, "sha512-BwR5KP3Es/CSht0xqBcUXS3qCAUVXwpRKsV2+arxeb65atasuXG9LykC9Ab10Cw3s2raH92ZqOeILaQbsB2ACg=="],
-
     "@types/cookie": ["@types/cookie@0.6.0", "", {}, "sha512-4Kh9a6B2bQciAhf7FSuMRRkUWecJgJu9nPnx3yzpsfXX/c50REIqpHY4C82bXP90qrLtXtkDxTZosYO3UpOwlA=="],
 
     "@types/d3-array": ["@types/d3-array@3.2.2", "", {}, "sha512-hOLWVbm7uRza0BYXpIIW5pxfrKe0W+D5lrFiAEYR+pb6w3N2SwSMaJbXdUfSEv+dT4MfHBLtn5js0LAWaO6otw=="],
@@ -221,42 +216,24 @@
 
     "acorn": ["acorn@8.16.0", "", { "bin": { "acorn": "bin/acorn" } }, "sha512-UVJyE9MttOsBQIDKw1skb9nAwQuR5wuGD3+82K6JgJlm/Y+KI92oNsMNGZCYdDsVtRHSak0pcV5Dno5+4jh9sw=="],
 
-    "ansi-styles": ["ansi-styles@4.3.0", "", { "dependencies": { "color-convert": "2.0.1" } }, "sha512-zbB9rCJAT1rbjiVDb2hqKFHNYLxgtk8NURxZ3IZwD3F6NtxbXZQCnnSi1Lkx+IDohdPlFp222wVALIheZJQSEg=="],
-
-    "apache-arrow": ["apache-arrow@21.1.0", "", { "dependencies": { "@swc/helpers": "0.5.21", "@types/command-line-args": "5.2.3", "@types/command-line-usage": "5.0.4", "@types/node": "24.12.2", "command-line-args": "6.0.2", "command-line-usage": "7.0.4", "flatbuffers": "25.9.23", "json-bignum": "0.0.3", "tslib": "2.8.1" }, "bin": { "arrow2csv": "bin/arrow2csv.js" } }, "sha512-kQrYLxhC+NTVVZ4CCzGF6L/uPVOzJmD1T3XgbiUnP7oTeVFOFgEUu6IKNwCDkpFoBVqDKQivlX4RUFqqnWFlEA=="],
-
     "aria-query": ["aria-query@5.3.1", "", {}, "sha512-Z/ZeOgVl7bcSYZ/u/rh0fOpvEpq//LZmdbkXyc7syVzjPAhfOa9ebsdTSjEBDU4vs5nC98Kfduj1uFo0qyET3g=="],
 
     "arkregex": ["arkregex@0.0.5", "", { "dependencies": { "@ark/util": "0.56.0" } }, "sha512-ncYjBdLlh5/QnVsAA8De16Tc9EqmYM7y/WU9j+236KcyYNUXogpz3sC4ATIZYzzLxwI+0sEOaQLEmLmRleaEXw=="],
 
     "arktype": ["arktype@2.2.0", "", { "dependencies": { "@ark/schema": "0.56.0", "@ark/util": "0.56.0", "arkregex": "0.0.5" } }, "sha512-t54MZ7ti5BhOEvzEkgKnWvqj+UbDfWig+DHr5I34xatymPusKLS0lQpNJd8M6DzmIto2QGszHfNKoFIT8tMCZQ=="],
 
-    "array-back": ["array-back@6.2.3", "", {}, "sha512-SGDvmg6QTYiTxCBkYVmThcoa67uLl35pyzRHdpCGBOcqFy6BtwnphoFPk7LhJshD+Yk1Kt35WGWeZPTgwR4Fhw=="],
-
     "axobject-query": ["axobject-query@4.1.0", "", {}, "sha512-qIj0G9wZbMGNLjLmg1PT6v2mE9AH2zlnADJD/2tC6E00hgmhUOfEB6greHPAfLRSufHqROIUTkw6E+M3lH0PTQ=="],
 
     "bits-ui": ["bits-ui@2.18.0", "", { "dependencies": { "@floating-ui/core": "1.7.5", "@floating-ui/dom": "1.7.6", "esm-env": "1.2.2", "runed": "0.35.1", "svelte-toolbelt": "0.10.6", "tabbable": "6.4.0" }, "peerDependencies": { "@internationalized/date": "3.12.1", "svelte": "5.55.5" } }, "sha512-GLOBZRVy3hxNHIQ2MpD/+5aK9KcBFZRhUJtZ1UDABXdlVR4K6zFpgt4T+Rwuhf2sQzlc6yK1q/DprHPjwT4Pjw=="],
 
     "camelcase": ["camelcase@8.0.0", "", {}, "sha512-8WB3Jcas3swSvjIeA2yvCJ+Miyz5l1ZmB6HFb9R1317dt9LCQoswg/BGrmAmkWVEszSrrg4RwmO46qIm2OEnSA=="],
 
-    "chalk": ["chalk@4.1.2", "", { "dependencies": { "ansi-styles": "4.3.0", "supports-color": "7.2.0" } }, "sha512-oKnbhFyRIXpUuez8iBMmyEa4nbj4IOQyuhc/wy9kY7/WVPcwIO9VA668Pu8RkO7+0G76SLROeyw9CpQ061i4mA=="],
-
-    "chalk-template": ["chalk-template@0.4.0", "", { "dependencies": { "chalk": "4.1.2" } }, "sha512-/ghrgmhfY8RaSdeo43hNXxpoHAtxdbskUHjPpfqUWGttFgycUhYPGx3YZBCnUCvOa7Doivn1IZec3DEGFoMgLg=="],
-
     "chokidar": ["chokidar@4.0.3", "", { "dependencies": { "readdirp": "4.1.2" } }, "sha512-Qgzu8kfBvo+cA4962jnP1KkS6Dop5NS6g7R5LFYJr4b8Ub94PPQXUksCw9PvXoeXPRRddRNC5C1JQUR2SMGtnA=="],
 
     "class-validator": ["class-validator@0.14.4", "", { "dependencies": { "@types/validator": "13.15.10", "libphonenumber-js": "1.12.42", "validator": "13.15.35" } }, "sha512-AwNusCCam51q703dW82x95tOqQp6oC9HNUl724KxJJOfnKscI8dOloXFgyez7LbTTKWuRBA37FScqVbJEoq8Yw=="],
 
     "clsx": ["clsx@2.1.1", "", {}, "sha512-eYm0QWBtUrBWZWG0d386OGAw16Z995PiOVo2B7bjWSbHedGl5e0ZWaq65kOGgUSNesEIDkB9ISbTg/JK9dhCZA=="],
 
-    "color-convert": ["color-convert@2.0.1", "", { "dependencies": { "color-name": "1.1.4" } }, "sha512-RRECPsj7iu/xb5oKYcsFHSppFNnsj/52OVTRKb4zP5onXwVF3zVmmToNcOfGC+CRDpfK/U584fMg38ZHCaElKQ=="],
-
-    "color-name": ["color-name@1.1.4", "", {}, "sha512-dOy+3AuW3a2wNbZHIuMZpTcgjGuLU/uBL/ubcZF9OXbDo8ff4O8yVp5Bf0efS8uEoYo5q4Fx7dY9OgQGXgAsQA=="],
-
-    "command-line-args": ["command-line-args@6.0.2", "", { "dependencies": { "array-back": "6.2.3", "find-replace": "5.0.2", "lodash.camelcase": "4.3.0", "typical": "7.3.0" } }, "sha512-AIjYVxrV9X752LmPDLbVYv8aMCuHPSLZJXEo2qo/xJfv+NYhaZ4sMSF01rM+gHPaMgvPM0l5D/F+Qx+i2WfSmQ=="],
-
-    "command-line-usage": ["command-line-usage@7.0.4", "", { "dependencies": { "array-back": "6.2.3", "chalk-template": "0.4.0", "table-layout": "4.1.1", "typical": "7.3.0" } }, "sha512-85UdvzTNx/+s5CkSgBm/0hzP80RFHAa7PsfeADE5ezZF3uHz3/Tqj9gIKGT9PTtpycc3Ua64T0oVulGfKxzfqg=="],
-
     "commander": ["commander@14.0.3", "", {}, "sha512-H+y0Jo/T1RZ9qPP4Eh1pkcQcLRglraJaSLoyOtHxu6AapkjWVCy2Sit1QQ4x3Dng8qDlSsZEet7g5Pq06MvTgw=="],
 
     "cookie": ["cookie@0.6.0", "", {}, "sha512-U71cyTamuh1CRNCfpGY6to28lxvNwPG4Guz/EVjgf3Jmzv0vlDp1atT9eS5dDjMYHucpHbWns6Lwf3BKz6svdw=="],
@@ -341,17 +318,13 @@
 
     "fdir": ["fdir@6.5.0", "", { "optionalDependencies": { "picomatch": "4.0.4" } }, "sha512-tIbYtZbucOs0BRGqPJkshJUYdL+SDH7dVM8gjy+ERp3WAUjLEFJE+02kanyHtwjWOnwrKYBiwAmM0p4kLJAnXg=="],
 
-    "find-replace": ["find-replace@5.0.2", "", {}, "sha512-Y45BAiE3mz2QsrN2fb5QEtO4qb44NcS7en/0y9PEVsg351HsLeVclP8QPMH79Le9sH3rs5RSwJu99W0WPZO43Q=="],
-
-    "flatbuffers": ["flatbuffers@25.9.23", "", {}, "sha512-MI1qs7Lo4Syw0EOzUl0xjs2lsoeqFku44KpngfIduHBYvzm8h2+7K8YMQh1JtVVVrUvhLpNwqVi4DERegUJhPQ=="],
-
     "formsnap": ["formsnap@2.0.1", "", { "dependencies": { "svelte-toolbelt": "0.5.0" }, "peerDependencies": { "svelte": "5.55.5", "sveltekit-superforms": "2.30.1" } }, "sha512-iJSe4YKd/W6WhLwKDVJU9FQeaJRpEFuolhju7ZXlRpUVyDdqFdMP8AUBICgnVvQPyP41IPAlBa/v0Eo35iE6wQ=="],
 
     "fsevents": ["fsevents@2.3.3", "", { "os": "darwin" }, "sha512-5xoDfX+fL7faATnagmWPpbFtwh/R77WmMMqqHGS65C3vvB0YHrgF+B1YmZ3441tMj5n63k0212XNoJwzlhffQw=="],
 
     "graceful-fs": ["graceful-fs@4.2.11", "", {}, "sha512-RbJ5/jmFcNNCcDV5o9eTnBLJ/HszWV0P73bc+Ff4nS/rJj+YaS6IGyiOL0VoBYX+l1Wrl3k63h/KrH+nhJ0XvQ=="],
 
-    "has-flag": ["has-flag@4.0.0", "", {}, "sha512-EykJT/Q1KjTWctppgIAgfSO0tKVuZUjhgMr17kqTumMl6Afv3EISleU7qZUzoXDFTAHTDC4NOoG/ZxU3EvlMPQ=="],
+    "hyparquet": ["hyparquet@1.25.6", "", {}, "sha512-Q9W5IjkVch3ZMnYd4qFv2q8suu5Jc36yt7J+zUNM9grwnP1S189icp0jdEQKM5HJvQkTVy8NMiQ8n/dM5QAt1A=="],
 
     "iconv-lite": ["iconv-lite@0.6.3", "", { "dependencies": { "safer-buffer": "2.1.2" } }, "sha512-4fCk79wshMdzMp2rH06qWrJE4iolqLhCUH+OiuIgU++RB0+94NlDL81atO7GX55uUKueo0txHNtvEyI6D7WdMw=="],
 
@@ -365,8 +338,6 @@
 
     "joi": ["joi@17.13.3", "", { "dependencies": { "@hapi/hoek": "9.3.0", "@hapi/topo": "5.1.0", "@sideway/address": "4.1.5", "@sideway/formula": "3.0.1", "@sideway/pinpoint": "2.0.0" } }, "sha512-otDA4ldcIx+ZXsKHWmp0YizCweVRZG96J10b0FevjfuncLO1oX59THoAmHkNubYJ+9gWsYsp5k8v4ib6oDv1fA=="],
 
-    "json-bignum": ["json-bignum@0.0.3", "", {}, "sha512-2WHyXj3OfHSgNyuzDbSxI1w2jgw5gkWSWhS7Qg4bWXx1nLk3jnbwfUeS0PSba3IzpTUWdHxBieELUzXRjQB2zg=="],
-
     "json-schema-to-ts": ["json-schema-to-ts@3.1.1", "", { "dependencies": { "@babel/runtime": "7.29.2", "ts-algebra": "2.0.0" } }, "sha512-+DWg8jCJG2TEnpy7kOm/7/AxaYoaRbjVB4LFZLySZlWn8exGs3A4OLJR966cVvU26N7X9TWxl+Jsw7dzAqKT6g=="],
 
     "kleur": ["kleur@4.1.5", "", {}, "sha512-o+NO+8WrRiQEE4/7nwRJhN1HWpVmJm511pBHUxPLtp0BUISzlBplORYSmTclCnJvQq2tKu/sgl3xVpkc7ZWuQQ=="],
@@ -401,8 +372,6 @@
 
     "locate-character": ["locate-character@3.0.0", "", {}, "sha512-SW13ws7BjaeJ6p7Q6CO2nchbYEc3X3J6WrmTTDto7yMPqVSZTUyY5Tjbid+Ab8gLnATtygYtiDIJGQRRn2ZOiA=="],
 
-    "lodash.camelcase": ["lodash.camelcase@4.3.0", "", {}, "sha512-TwuEnCnxbc3rAvhf/LbG7tJUDzhqXyFnv3dtzLOPgCG/hODL7WFnsbwktkD7yUV0RrreP/l1PALq/YSg6VvjlA=="],
-
     "lz-string": ["lz-string@1.5.0", "", { "bin": { "lz-string": "bin/bin.js" } }, "sha512-h5bgJWpxJNswbU7qCrV0tIKQCaS3blPDrqKWx+QxzuzL1zGUzij9XCWLrSLsJPu5t+eWA/ycetzYAO5IOMcWAQ=="],
 
     "magic-string": ["magic-string@0.30.21", "", { "dependencies": { "@jridgewell/sourcemap-codec": "1.5.5" } }, "sha512-vd2F4YUyEXKGcLHoq+TEyCjxueSeHnFxyyjNp80yg0XV4vUhnDer/lvvlqM/arB5bXQN5K2/3oinyCRyx8T2CQ=="],
@@ -431,8 +400,6 @@
 
     "paneforge": ["paneforge@1.0.2", "", { "dependencies": { "runed": "0.23.4", "svelte-toolbelt": "0.9.3" }, "peerDependencies": { "svelte": "5.55.5" } }, "sha512-KzmIXQH1wCfwZ4RsMohD/IUtEjVhteR+c+ulb/CHYJHX8SuDXoJmChtsc/Xs5Wl8NHS4L5Q7cxL8MG40gSU1bA=="],
 
-    "parquet-wasm": ["parquet-wasm@0.7.1", "", {}, "sha512-fjEGpMApzt3mpI2pUxdRgQGu5G+s4nr0vm5xn43JO7jxdYzzu2fHrVrTHtfeEhtB6vfvTzJBz0WydDYzLWvszQ=="],
-
     "phosphor-svelte": ["phosphor-svelte@3.1.0", "", { "dependencies": { "estree-walker": "3.0.3", "magic-string": "0.30.21" }, "optionalDependencies": { "vite": "8.0.10" }, "peerDependencies": { "svelte": "5.55.5" } }, "sha512-nldtxx+XCgNREvrb7O5xgDsefytXpSkPTx8Rnu3f2qQCUZLDV1rLxYSd2Jcwckuo9lZB1qKMqGR17P4UDC0PrA=="],
 
     "picocolors": ["picocolors@1.1.1", "", {}, "sha512-xceH2snhtb5M9liqDsmEw56le376mTZkEX/jEb/RxNFyegNul7eNslCXP9FDj/Lcu0X8KEyMceP2ntpaHrDEVA=="],
@@ -471,8 +438,6 @@
 
     "superstruct": ["superstruct@2.0.2", "", {}, "sha512-uV+TFRZdXsqXTL2pRvujROjdZQ4RAlBUS5BTh9IGm+jTqQntYThciG/qu57Gs69yjnVUSqdxF9YLmSnpupBW9A=="],
 
-    "supports-color": ["supports-color@7.2.0", "", { "dependencies": { "has-flag": "4.0.0" } }, "sha512-qpCAvRl9stuOHveKsn7HncJRvv501qIacKzQlO/+Lwxc9+0q2wLyv4Dfvt80/DPn2pqOBsJdDiogXGR9+OvwRw=="],
-
     "svelte": ["svelte@5.55.5", "", { "dependencies": { "@jridgewell/remapping": "2.3.5", "@jridgewell/sourcemap-codec": "1.5.5", "@sveltejs/acorn-typescript": "1.0.9", "@types/estree": "1.0.8", "@types/trusted-types": "2.0.7", "acorn": "8.16.0", "aria-query": "5.3.1", "axobject-query": "4.1.0", "clsx": "2.1.1", "devalue": "5.7.1", "esm-env": "1.2.2", "esrap": "2.2.5", "is-reference": "3.0.3", "locate-character": "3.0.0", "magic-string": "0.30.21", "zimmerframe": "1.1.4" } }, "sha512-2uCs/LZ9us+AktdzYJM8OcxQ8qnPS1kpaO7syGT/MgO+6Qr1Ybl+TqPq+97u7PHqmmMlye5ZkoyXONy5mjjAbw=="],
 
     "svelte-check": ["svelte-check@4.4.6", "", { "dependencies": { "@jridgewell/trace-mapping": "0.3.31", "chokidar": "4.0.3", "fdir": "6.5.0", "picocolors": "1.1.1", "sade": "1.8.1" }, "peerDependencies": { "svelte": "5.55.5", "typescript": "6.0.3" }, "bin": { "svelte-check": "bin/svelte-check" } }, "sha512-kP1zG81EWaFe9ZyTv4ZXv44Csi6Pkdpb7S3oj6m+K2ec/IcDg/a8LsFsnVLqm2nxtkSwsd5xPj/qFkTBgXHXjg=="],
@@ -485,8 +450,6 @@
 
     "tabbable": ["tabbable@6.4.0", "", {}, "sha512-05PUHKSNE8ou2dwIxTngl4EzcnsCDZGJ/iCLtDflR/SHB/ny14rXc+qU5P4mG9JkusiV7EivzY9Mhm55AzAvCg=="],
 
-    "table-layout": ["table-layout@4.1.1", "", { "dependencies": { "array-back": "6.2.3", "wordwrapjs": "5.1.1" } }, "sha512-iK5/YhZxq5GO5z8wb0bY1317uDF3Zjpha0QFFLA8/trAoiLbQD0HUbMesEaxyzUgDxi2QlcbM8IvqOlEjgoXBA=="],
-
     "tailwind-merge": ["tailwind-merge@3.5.0", "", {}, "sha512-I8K9wewnVDkL1NTGoqWmVEIlUcB9gFriAEkXkfCjX5ib8ezGxtR3xD7iZIxrfArjEsH7F1CHD4RFUtxefdqV/A=="],
 
     "tailwind-variants": ["tailwind-variants@3.2.2", "", { "optionalDependencies": { "tailwind-merge": "3.5.0" }, "peerDependencies": { "tailwindcss": "4.2.4" } }, "sha512-Mi4kHeMTLvKlM98XPnK+7HoBPmf4gygdFmqQPaDivc3DpYS6aIY6KiG/PgThrGvii5YZJqRsPz0aPyhoFzmZgg=="],
@@ -517,8 +480,6 @@
 
     "typescript": ["typescript@6.0.3", "", { "bin": { "tsc": "bin/tsc", "tsserver": "bin/tsserver" } }, "sha512-y2TvuxSZPDyQakkFRPZHKFm+KKVqIisdg9/CZwm9ftvKXLP8NRWj38/ODjNbr43SsoXqNuAisEf1GdCxqWcdBw=="],
 
-    "typical": ["typical@7.3.0", "", {}, "sha512-ya4mg/30vm+DOWfBg4YK3j2WD6TWtRkCbasOJr40CseYENzCUby/7rIvXA99JGsQHeNxLbnXdyLLxKSv3tauFw=="],
-
     "undici-types": ["undici-types@7.16.0", "", {}, "sha512-Zz+aZWSj8LE6zoxD+xrjh4VfkIG8Ya6LvYkZqtUQGJPZjYl53ypCaUwWqo7eI0x66KBGeRo+mlBEkMSeSZ38Nw=="],
 
     "valibot": ["valibot@1.3.1", "", { "optionalDependencies": { "typescript": "6.0.3" } }, "sha512-sfdRir/QFM0JaF22hqTroPc5xy4DimuGQVKFrzF1YfGwaS1nJot3Y8VqMdLO2Lg27fMzat2yD3pY5PbAYO39Gg=="],
@@ -531,8 +492,6 @@
 
     "vitefu": ["vitefu@1.1.3", "", { "optionalDependencies": { "vite": "8.0.10" } }, "sha512-ub4okH7Z5KLjb6hDyjqrGXqWtWvoYdU3IGm/NorpgHncKoLTCfRIbvlhBm7r0YstIaQRYlp4yEbFqDcKSzXSSg=="],
 
-    "wordwrapjs": ["wordwrapjs@5.1.1", "", {}, "sha512-0yweIbkINJodk27gX9LBGMzyQdBDan3s/dEAiwBOj+Mf0PPyWL6/rikalkv8EeD0E8jm4o5RXEOrFTP3NXbhJg=="],
-
     "yup": ["yup@1.7.1", "", { "dependencies": { "property-expr": "2.0.6", "tiny-case": "1.0.3", "toposort": "2.0.2", "type-fest": "2.19.0" } }, "sha512-GKHFX2nXul2/4Dtfxhozv701jLQHdf6J34YDh2cEkpqoo8le5Mg6/LrdseVLrFarmFygZTlfIhHx/QKfb/QWXw=="],
 
     "zimmerframe": ["zimmerframe@1.1.4", "", {}, "sha512-B58NGBEoc8Y9MWWCQGl/gq9xBCe4IiKM0a2x7GZdQKOW5Exr8S1W24J6OgM1njK8xCRGvAJIL/MxXHf6SkmQKQ=="],

package.json

@@ -41,8 +41,7 @@
 		"vite": "^8.0.7"
 	},
 	"dependencies": {
-		"apache-arrow": "^21.1.0",
-		"mediabunny": "^1.42.0",
-		"parquet-wasm": "^0.7.1"
+		"hyparquet": "^1.25.6",
+		"mediabunny": "^1.42.0"
 	}
 }

src/lib/api/parquet.ts

@@ -1,21 +1,4 @@
-import * as arrow from 'apache-arrow';
-
-let wasmReady: Promise<void> | null = null;
-let readParquetFn: ((bytes: Uint8Array) => { intoIPCStream: () => Uint8Array }) | null = null;
-
-async function ensureWasm(): Promise<void> {
-	if (wasmReady) return wasmReady;
-	wasmReady = (async () => {
-		const mod = await import('parquet-wasm');
-		const init = (mod as unknown as { default?: () => Promise<unknown> }).default;
-		if (typeof init === 'function') await init();
-		readParquetFn = (mod as unknown as { readParquet: typeof readParquetFn }).readParquet!;
-	})().catch((err) => {
-		wasmReady = null;
-		throw err;
-	});
-	return wasmReady;
-}
+import { parquetReadObjects } from 'hyparquet';
 
 export type ParquetFetchOptions = {
 	fetch?: typeof fetch;
@@ -24,29 +7,36 @@ export type ParquetFetchOptions = {
 
 /**
  * Fetch a parquet file over HTTP and return its rows as plain JS objects.
- * Timestamp columns are converted to ISO strings; BigInts become numbers.
- * Nested struct/list columns are returned as Arrow proxies (we don't read any).
+ * Backed by `hyparquet` (pure-JS, ~30KB) instead of `parquet-wasm` (6.3MB
+ * WASM + init) — the index parquets are tiny (~1–2KB) so a JS reader is
+ * dramatically faster end-to-end despite being slower per-byte.
+ *
+ * Timestamp columns surface as `Date` from hyparquet; we normalize them to
+ * ISO strings here so the rest of the app sees a stable shape. BigInts are
+ * downcast to numbers (every numeric column we read fits in a JS number).
  */
 export async function fetchParquetRows<T = Record<string, unknown>>(
 	url: string,
 	opts: ParquetFetchOptions = {}
 ): Promise<T[]> {
-	await ensureWasm();
 	const f = opts.fetch ?? fetch;
 	const res = await f(url, { signal: opts.signal });
 	if (!res.ok) throw new Error(`parquet fetch ${url}: ${res.status} ${res.statusText}`);
-	const bytes = new Uint8Array(await res.arrayBuffer());
-	const table = arrow.tableFromIPC(readParquetFn!(bytes).intoIPCStream());
+	const buffer = await res.arrayBuffer();
+	const file = {
+		byteLength: buffer.byteLength,
+		slice(start: number, end?: number): Promise<ArrayBuffer> {
+			return Promise.resolve(buffer.slice(start, end));
+		}
+	};
 
-	const timestamps = new Set(
-		table.schema.fields.filter((f) => arrow.DataType.isTimestamp(f.type)).map((f) => f.name)
-	);
+	const rows = await parquetReadObjects({ file });
 
-	return table.toArray().map((row) => {
+	return rows.map((row) => {
 		const out: Record<string, unknown> = {};
-		for (const [k, v] of Object.entries(row as Record<string, unknown>)) {
+		for (const [k, v] of Object.entries(row)) {
 			if (v == null) out[k] = v;
-			else if (timestamps.has(k)) out[k] = new Date(Number(v)).toISOString();
+			else if (v instanceof Date) out[k] = v.toISOString();
 			else if (typeof v === 'bigint') out[k] = Number(v);
 			else out[k] = v;
 		}

src/routes/+layout.ts

@@ -1,4 +1,4 @@
-// Data is loaded from parquet files via parquet-wasm in the browser; disable
+// Data is loaded from parquet files via hyparquet in the browser; disable
 // SSR so the load functions run only on the client.
 export const ssr = false;
 export const prerender = false;