while.js

const _effect = evaluator => ({ type: 'effect', evaluator });
const _mut = evaluator => ({ type: 'mut', evaluator });

const _while = (condition, body) => env => {
    if (condition(env)) {
        const state = body.reduce((env, elem) => {
            if (elem.type === 'effect') {
                void elem.evaluator(env);
                return env;
            } else if (elem.type === 'mut') {
                return elem.evaluator(env);
            }
        }, env);

        _while(condition, body)(state);
    }
};

_while(
    ({ i }) => i < 10,
    [
        _effect(({ i }) => console.log(i)),
        _mut(({ i }) => ({ i: i + 1 }))
    ]
)({ i: 0 })