Add the possibility to generate non empty array types

[adrndfn]

Description

We tried to generate a parameter type with a non empty array with "minItems": 1 json schema conf ( part of our openapi.json ) :

          {
            "name": "nodeIds",
            "in": "query",
            "required": false,
            "schema": {
              "type": "array",
              "items": {
                "type": "integer"
              },
              "title": "Contextual node ids",
              "examples": [
                [
                  1,
                  2,
                  3
                ]
              ],
              "minItems": 1,
              "default": []
            }
          },

We get this generated code in types.gen.ts :

/**
* Contextual node ids
*/
nodeIds: Array<number>;

But we would expect to generate something like :

/**
* Contextual node ids
*/
nodeIds: [number, ...number[]];

Here is opeanapi-ts.config.ts

import { defaultPlugins, defineConfig } from "@hey-api/openapi-ts";

export default defineConfig({
    input: "openapi.json",
    output: { format: "biome", path: "./src/client" },
    plugins: [
        ...defaultPlugins,
        "@hey-api/client-fetch",
        { name: "@hey-api/transformers", dates: true },
        { name: "@hey-api/sdk", transformer: true },
        {
            name: "@hey-api/typescript",
            readOnlyWriteOnlyBehavior: "off",
        },
    ],
});

And related comment to generate types.gen.ts

rm -rf ./src/client && openapi-ts -f ./openapi-ts.config.ts

[dosubot]

Hi @adrndfn! I'm Dosu and I’m helping the openapi-ts team.

Currently, openapi-ts generates arrays with minItems constraints as Array in TypeScript, not as non-empty tuple spread types like [number, ...number[]]. There isn't a documented configuration or plugin to change this behavior or enforce non-empty arrays in the generated types. This means the feature you want isn't natively supported at the moment, and the generated output will remain Array even with minItems: 1 in your schema. You can review more about the TypeScript output in the official docs here.

To reply, just mention @dosu.

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