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

a specification for maplibre styles

import {getType} from '../util/get_type';
import {ValidationError} from '../error/validation_error';

export function validateArray(options) {
    const array = options.value;
    const arraySpec = options.valueSpec;
    const validateSpec = options.validateSpec;
    const style = options.style;
    const styleSpec = options.styleSpec;
    const key = options.key;
    const validateArrayElement = options.arrayElementValidator || validateSpec;

    if (getType(array) !== 'array') {
        return [new ValidationError(key, array, `array expected, ${getType(array)} found`)];
    }

    if (arraySpec.length && array.length !== arraySpec.length) {
        return [
            new ValidationError(
                key,
                array,
                `array length ${arraySpec.length} expected, length ${array.length} found`
            )
        ];
    }

    let arrayElementSpec = {
        type: arraySpec.value,
        values: arraySpec.values
    };

    if (styleSpec.$version < 7) {
        arrayElementSpec['function'] = arraySpec.function;
    }

    if (getType(arraySpec.value) === 'object') {
        arrayElementSpec = arraySpec.value;
    }

    let errors = [];
    for (let i = 0; i < array.length; i++) {
        errors = errors.concat(
            validateArrayElement({
                array,
                arrayIndex: i,
                value: array[i],
                valueSpec: arrayElementSpec,
                validateSpec: options.validateSpec,
                style,
                styleSpec,
                key: `${key}[${i}]`
            })
        );
    }
    return errors;
}