convexRules

Convex guidelines

Function guidelines

New function syntax

• ALWAYS use the new function syntax for Convex functions. For example:

import { query } from "./_generated/server";
import { v } from "convex/values";
export const f = query({
    args: {},
    returns: v.null(),
    handler: async (ctx, args) => {
    // Function body
    },
});

Http endpoint syntax

• HTTP endpoints are defined in convex/http.ts and require an httpAction decorator. For example:

import { httpRouter } from "convex/server";
import { httpAction } from "./_generated/server";
const http = httpRouter();
http.route({
    path: "/echo",
    method: "POST",
    handler: httpAction(async (ctx, req) => {
    const body = await req.bytes();
    return new Response(body, { status: 200 });
    }),
});

• HTTP endpoints are always registered at the exact path you specify in the path field. For example, if you specify /api/someRoute, the endpoint will be registered at /api/someRoute.

Validators

• Below is an example of an array validator:

import { mutation } from "./_generated/server";
import { v } from "convex/values";

export default mutation({
args: {
    simpleArray: v.array(v.union(v.string(), v.number())),
},
handler: async (ctx, args) => {
    //...
},
});

• Below is an example of a schema with validators that codify a discriminated union type:

import { defineSchema, defineTable } from "convex/server";
import { v } from "convex/values";

export default defineSchema({
    results: defineTable(
        v.union(
            v.object({
                kind: v.literal("error"),
                errorMessage: v.string(),
            }),
            v.object({
                kind: v.literal("success"),
                value: v.number(),
            }),
        ),
    )
});

• Always use the v.null() validator when returning a null value. Below is an example query that returns a null value:

import { query } from "./_generated/server";
import { v } from "convex/values";

export const exampleQuery = query({
  args: {},
  returns: v.null(),
  handler: async (ctx, args) => {
      console.log("This query returns a null value");
      return null;
  },
});

• Here are the valid Convex types along with their respective validators: Convex Type | TS/JS type | Example Usage | Validator for argument validation and schemas | Notes | | ----------- | ------------| -----------------------| -----------------------------------------------| ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| | Id | string | doc._id | v.id(tableName) | | | Null | null | null | v.null() | JavaScript's undefined is not a valid Convex value. Functions the return undefined or do not return will return null when called from a client. Use null instead. | | Int64 | bigint | 3n | v.int64() | Int64s only support BigInts between -2^63 and 2^63-1. Convex supports bigints in most modern browsers. | | Float64 | number | 3.1 | v.number() | Convex supports all IEEE-754 double-precision floating point numbers (such as NaNs). Inf and NaN are JSON serialized as strings. | | Boolean | boolean | true | v.boolean() | | String | string | "abc" | v.string() | Strings are stored as UTF-8 and must be valid Unicode sequences. Strings must be smaller than the 1MB total size limit when encoded as UTF-8. | | Bytes | ArrayBuffer | new ArrayBuffer(8) | v.bytes() | Convex supports first class bytestrings, passed in as ArrayBuffers. Bytestrings must be smaller than the 1MB total size limit for Convex types. | | Array | Array | [1, 3.2, "abc"] | v.array(values) | Arrays can have at most 8192 values. | | Object | Object | {a: "abc"} | v.object({property: value}) | Convex only supports "plain old JavaScript objects" (objects that do not have a custom prototype). Objects can have at most 1024 entries. Field names must be nonempty and not start with "$" or "". | | Record | Record | {"a": "1", "b": "2"} | v.record(keys, values) | Records are objects at runtime, but can have dynamic keys. Keys must be only ASCII characters, nonempty, and not start with "$" or "". |