@maplibre/maplibre-gl-style-spec/src/validate/validate_terrain.ts

a specification for maplibre styles

import {ValidationError} from '../error/validation_error';
import {getType} from '../util/get_type';
import type {StyleSpecification, TerrainSpecification} from '../types.g';
import v8 from '../reference/v8.json' with {type: 'json'};

export function validateTerrain(options: {
    value: TerrainSpecification;
    styleSpec: typeof v8;
    style: StyleSpecification;
    validateSpec: Function;
}): ValidationError[] {
    const terrain = options.value;
    const styleSpec = options.styleSpec;
    const terrainSpec = styleSpec.terrain;
    const style = options.style;

    let errors = [];

    const rootType = getType(terrain);
    if (terrain === undefined) {
        return errors;
    } else if (rootType !== 'object') {
        errors = errors.concat([
            new ValidationError('terrain', terrain, `object expected, ${rootType} found`)
        ]);
        return errors;
    }

    for (const key in terrain) {
        if (terrainSpec[key]) {
            errors = errors.concat(
                options.validateSpec({
                    key,
                    value: terrain[key],
                    valueSpec: terrainSpec[key],
                    validateSpec: options.validateSpec,
                    style,
                    styleSpec
                })
            );
        } else {
            errors = errors.concat([
                new ValidationError(key, terrain[key], `unknown property "${key}"`)
            ]);
        }
    }

    return errors;
}