code: function proxy(context, strict) {
      return new Proxy(context || {}, {
          get(target, key) {
              if (key === symbol.map) return target
              if (key === "toString") return () => toPrimitive([target])
              if (Reflect.has(target, key)) return create(Reflect.get(target, key))
  
              if (!strict) return create([key])
          },
          set(target, key, value) {
              if (is.box(value)) {
                  return Reflect.set(target, key, value)
              }
          },
          has(target, key) {
              return Reflect.has(target, key)
          }
      })
  }
docs: bitbox.map(mapping, context)
  @param {Object} mapping
  @param {Function} context