/**
 * Converts an environment variable to a `boolean`
 * Returns `false` if the value is `"false"`, `"0"` or `undefined`.
 * Otherwise, returns `true`.
 */
export declare const parseBooleanEnvVariable: (variable: string | undefined) => boolean;
/**
 * Creates a function that returns the passed value if the given `condition` evaluates to `true`,
 * or `undefined` (or the specified `fallback` value) otherwise.
 * Arrays are treated specially. If the passed `value` is an array, and the `condition`
 * evaluates to `true`, a new array is returned with all the falsey values in the original array
 * removed. If the `condition` evaluates to `false`, and the `fallback` value is falsey,
 * the fallback value will default to an empty array. This is to make it convenient to compose
 * configurations that expect arrays of strings or objects and be able to spread the arrays
 * without having to worry about spreading `undefined` (`[...undefined]`)
 * (which would be a runtime error).
 *
 * @example
 * ```javascript
 * const isCi = process.env.CI;
 * const isProd = process.env.NODE_ENV === 'production';
 * const isReact = process.env.REACT === 'true';
 *
 * const ifCi = createConditionalWithFallback(isCi);
 * const ifProd = createConditionalWithFallback(isProd);
 * const ifReact = createConditionalWithFallback(isReact);
 *
 * const deploymentTasks = [ifCi('yarn publish') || 'yarn test'];
 *
 * const babelConfig = {
 *  presets: compact([
 *   'babel-preset-env',
 *   ...ifReact(['babel-preset-react', ifProd('babel-preset-minify')])
 *  ]),
 * };
 * ```
 */
export declare function createConditionalWithFallback(condition: boolean): <T, F = undefined>(value: T, fallback?: F | undefined) => T extends any[] ? any[] | NonFalsey<F> | NonFalsey<T> : T | F;
declare type NonFalsey<T> = T extends (false | '' | 0) ? never : NonNullable<T>;
export declare const isTest: boolean;
export declare const isProduction: boolean;
export declare const isCi: boolean;
export declare const isDevelopment: boolean;
export declare const isDev: boolean;
export declare const isProd: boolean;
export declare const isHot: boolean;
export declare const isPreact: boolean;
export declare const isReact: boolean;
export declare const isEs5: boolean;
export declare const isEsNext: boolean;
export declare const isPerf: boolean;
export declare const shouldTypeCheck: boolean;
export declare const isDebug: boolean;
export declare const ifProd: <T, F = undefined>(value: T, fallback?: F | undefined) => T extends any[] ? any[] | NonFalsey<F> | NonFalsey<T> : T | F;
export declare const ifHot: <T, F = undefined>(value: T, fallback?: F | undefined) => T extends any[] ? any[] | NonFalsey<F> | NonFalsey<T> : T | F;
export declare const ifTest: <T, F = undefined>(value: T, fallback?: F | undefined) => T extends any[] ? any[] | NonFalsey<F> | NonFalsey<T> : T | F;
export declare const ifDev: <T, F = undefined>(value: T, fallback?: F | undefined) => T extends any[] ? any[] | NonFalsey<F> | NonFalsey<T> : T | F;
export declare const ifReact: <T, F = undefined>(value: T, fallback?: F | undefined) => T extends any[] ? any[] | NonFalsey<F> | NonFalsey<T> : T | F;
export declare const ifPreact: <T, F = undefined>(value: T, fallback?: F | undefined) => T extends any[] ? any[] | NonFalsey<F> | NonFalsey<T> : T | F;
export declare const ifEs5: <T, F = undefined>(value: T, fallback?: F | undefined) => T extends any[] ? any[] | NonFalsey<F> | NonFalsey<T> : T | F;
export declare const ifEsNext: <T, F = undefined>(value: T, fallback?: F | undefined) => T extends any[] ? any[] | NonFalsey<F> | NonFalsey<T> : T | F;
export declare const ifCi: <T, F = undefined>(value: T, fallback?: F | undefined) => T extends any[] ? any[] | NonFalsey<F> | NonFalsey<T> : T | F;
export declare const ifPerf: <T, F = undefined>(value: T, fallback?: F | undefined) => T extends any[] ? any[] | NonFalsey<F> | NonFalsey<T> : T | F;
export declare const ifDebug: <T, F = undefined>(value: T, fallback?: F | undefined) => T extends any[] ? any[] | NonFalsey<F> | NonFalsey<T> : T | F;
export {};