utils.ts

import {LDFlagChangeset, LDFlagSet} from 'launchdarkly-js-client-sdk';
import camelCase from 'lodash.camelcase';
import {LDReactOptions} from "./types";

/**
 * Transforms a set of flags so that their keys are camelCased. This function ignores
 * flag keys which start with `$`.
 *
 * @param rawFlags A mapping of flag keys and their values
 * @return A transformed `LDFlagSet` with camelCased flag keys
 */
export const camelCaseKeys = (rawFlags: LDFlagSet) => {
  const flags: LDFlagSet = {};
  for (const rawFlag in rawFlags) {
    // Exclude system keys
    if (rawFlag.indexOf('$') !== 0) {
      flags[camelCase(rawFlag)] = rawFlags[rawFlag]; // tslint:disable-line:no-unsafe-any
    }
  }

  return flags;
};

/**
 * Gets the flags to pass to the provider from the changeset.
 *
 * @param changes the `LDFlagChangeset` from the ldClient onchange handler.
 * @param targetFlags if targetFlags are specified, changes to other flags are ignored and not returned in the
 * flattened `LDFlagSet`
 * @param reactOptions reactOptions.useCamelCaseFlagKeys is used to determine whether to
 * @return an `LDFlagSet` with the current flag values from the LDFlagChangeset filtered by `targetFlags`
 * or null if none of the targetFlags were changed
 */
export const getFlattenedFlagsFromChangeset = (changes: LDFlagChangeset, targetFlags: LDFlagSet | undefined,
                                               reactOptions: LDReactOptions): LDFlagSet | null => {
  const flattened: LDFlagSet = {};
  for (const key in changes) {
    if (targetFlags === undefined || targetFlags[key] !== undefined) {
      // tslint:disable-next-line:no-unsafe-any
      const flagKey = reactOptions.useCamelCaseFlagKeys ? camelCase(key) : key;
      flattened[flagKey] = changes[key].current;
    }
  }
  return Object.keys(flattened).length > 0 ? flattened : null;
}

export default { camelCaseKeys, getFlattenedFlagsFromChangeset };