Wrote another truth table generator in Firefox console

truth_table_in_console.js

let and2 = (x, y) => {
  if (Boolean(x)) {
    return Boolean(y)
  } else {
    return false
  }
}

let or2 = (x, y) => {
  if (Boolean(x)) {
    return true
  } else {
    return Boolean(y)
  }
}


let andn = (...xs) => {
  let r = true
  for (let x of xs) {
    r = and2(x, r)
  }
  return r
}

let orn = (...xs) => {
  let r = false
  for (let x of xs) {
    r = or2(x, r)
  }
  return r
}


let and = (...xs) => { return { op: 'and', xs } }
let or = (...xs) => { return { op: 'or', xs } }

let evallit = (expr) => {
  if (!expr.op) {
    return Boolean(expr)
  }
  let rs = [];
  let { op, xs } = expr
  for (let x of xs) { rs.push(eval(x)) }
  if (op === 'and') {
    return andn(...rs)
  } else if (op === 'or') {
    return orn(...rs)
  }
}

let extract_vars = (expr) => {
  let extract_vars_rec = (expr, vars) => {
    if (!expr.op) {
      let x = expr
      if (typeof x === 'string') {
        if (!vars.includes(x)) { vars.push(x) }
      }
      return vars 
    }
    let { op, xs } = expr
    for (let x of xs) { extract_vars_rec(x, vars) }
    return vars
  }
  return extract_vars_rec(expr, [])
}

let generate_attempts = (vars) => {
  let attempts = []
  let num_of_attempts = Math.pow(2, vars.length)
  for (let ia = 0; ia < num_of_attempts; ia++) {
    let att = {}
    for (let iv = 0; iv < vars.length; iv++) {
      let guess = Math.floor(ia / Math.pow(2, iv)) % 2
      att[vars[iv]] = guess
    }
    attempts.push(att)
  }
  return attempts
}

// let vars = extract_vars()
// generate_attempts(vars)

let eval = (expr, att) => {
  if (!expr.op) {
    if (typeof expr === 'string') { return att[expr] }
    return Boolean(expr)
  }
  let rs = [];
  let { op, xs } = expr
  for (let x of xs) { rs.push(eval(x, att)) }
  if (op === 'and') {
    return andn(...rs)
  } else if (op === 'or') {
    return orn(...rs)
  }
}

let truth_table = (expr) => {
  let vars = extract_vars(expr)
  let attempts = generate_attempts(vars)
  let rs = []
  for (let att of attempts) {
    rs.push({...att, result: eval(expr, att)})
  }
  return rs
}

let test1 = and('x', 'y')
let test2 = and(and('x', 'y', or('y', 'z', 0)), or('x', 'i'))
JSON.stringify(truth_table(test2), null, 2)