3v0k4

mysql> SELECT title, genre, count(*) FROM films GROUP BY genre;

+-------------------+----------+----------+
| title             | genre    | count(*) |
+-------------------+----------+----------+
| Arrival           | scifi    |        1 |
| Blade Runner 2049 | thriller |        2 |
+-------------------+----------+----------+

3v0k4

mysql> SELECT title, genre, count(*) FROM films GROUP BY genre;

ERROR 1055 (42000): Expression #1 of SELECT list is not in GROUP BY clause and contains nonaggregated column 'some_database.films.title' which is not functionally dependent on columns in GROUP BY clause; this is incompatible with sql_mode=only_full_group_by

3v0k4

const procedural = s => {
  try {
    const parsed = JSON.parse(s);
    if (parsed.length > 0) {
      const first = parsed[0]
      const upperCased = first.toUpperCase()
      return  upperCased.concat('!')
    } else {
      return "empty array"
    }

3v0k4

const format = s => Right(s).map(upper).map(shout)

const functional = s => Right(s).chain(parse).chain(first).chain(format)


functional('["hello", "world"]')
// Right(HELLO!)

3v0k4

const format = array => {
  if (array.length > 0) {
    return array[0].toUpperCase().concat('!')
  } else {
    return "empty array"
  }
}

const procedural = s => {
  try {

3v0k4

const format = array => {
  if (array.length > 0) {
    return array[0].toUpperCase().concat('!')
  } else {
    return "empty array"
  }
}

const procedural = (s, callback) => {
  try {

3v0k4

const Box = x =>
  ({
    x
  })

const primitive = 1
const boxedPrimitive = Box(1)

3v0k4

const Box = x =>
  ({
    x,
    map: f => Box(f(x))
  })

const primitive = 1
const sum1 = primitive + 2 // 3

const boxedPrimitive = Box(1)

3v0k4

const Box = x =>
  ({
    x,
    map: f => Box(f(x)),
    chain: f => f(x)
  })

const boxedPrimitive = Box(1)
const sum = boxedPrimitive.chain(x => x + 2) // 3

3v0k4

const Right = x =>
  ({
    x,
    map: f => Right(f(x)),
    chain: f => f(x)
  })

const Left = x =>
  ({
    x,