Structured Field Values

What is this ?

This is a implementation of a RFC 8941: Structured Field Values for HTTP in JavaScript.

And also Date type in sfbis-02 is also supported.

DEMO

• https://jxck.github.io/structured-field-values/demo.html

Install

npm install structured-field-values

API

• decodeItem
• decodeList
• decodeDict
• encodeItem
• encodeList
• encodeDict

Primitives

Item

decodeItem

SFV has string and token and this module use Symbol for token.

And SFV has params for every item, so decoded token are always object with value & params.

decodeItem(`a`)    // Item { value: Symbol(a), params: null }
decodeItem(`"a"`)  // Item { value: `a`,       params: null }
decodeItem(`10`)   // Item { value: 10,        params: null }
decodeItem(`3.14`) // Item { value: 3.14,      params: null }
decodeItem(`?0`)   // Item { value: false,     params: null }

decodeItem(`@1659578233`)
// Item { value: new Date(`2022-08-04T01:57:13.000Z`), params: null }

decodeItem(`"a";x;y=?0;z=10`)
// Item { value: `a`, params: { x: true, y: false, z: 10 } }

Note: Symbol generated in decoder is registered globally as Shared Symbol, so you can handle them like.

const a = decodeItem(`a`).value // Symbol(a)
console.log(Symbol.keyFor(a)) // "a" (string)

encodeItem

encodeItem(Symbol.for('a')) // `a`
encodeItem("a")             // `"a"`
encodeItem(10)              // `10`
encodeItem(3.14)            // `3.14`
encodeItem(true)            // `?0`

encodeItem(new Item(Symbol.for('a'))) // `a`
encodeItem(new Item("a"))             // `"a"`
encodeItem(new Item(10))              // `10`
encodeItem(new Item(3.14))            // `3.14`
encodeItem(new Item(true))            // `?0`

encodeItem(new Item(new Date(1659578233000))) // 2022-08-04T01:57:13.000Z

encodeItem(new Item(`a`, { x: true, y: false, z: 10 })) // `"a";x;y=?0;z=10`

Note: JavaScript only supports number

encodeItem(decodeItem('1.0')) // '1' not '1.0'

List

decodeList

decodeList(`1,2,3`)
// [
//   Item { value: 1, params: null },
//   Item { value: 2, params: null },
//   Item { value: 3, params: null }
// ]

decodeList(`a;x,"b";y=?0,10,(1 2)`)
// [
//   Item { value: Symbol(a), params: { x: true } },
//   Item { value: `b`,       params: { y: false } },
//   Item { value: 10,        params: null },
//   Item { value: [
//                   { value: 1, params: null }
//                   { value: 2, params: null }
//                 ], params: null }
// ]

encodeList

// `1, 2, 3`
encodeList([1,2,3])
encodeList([
  new Item(1),
  new Item(2),
  new Item(3)
])

// `a;x, "b";y=?0, 10, (1 2)`
encodeList([
  new Item(Symbol.for('a'), { x: true  }),
  new Item(`b`,             { y: false }),
  new Item(10),
  new Item([1, 2])
])

Dict

decodeDict

decodeDict(`a=x, b="y", c=10, d=?0, e=(1 2)`)
// {
//   a: Item { value: Symbol(x), params: null },
//   b: Item { value: 'y',       params: null },
//   c: Item { value: 10,        params: null },
//   d: Item { value: false,     params: null },
//   e: Item { value: [
//                      Item { value: 1, params: null }
//                      Item { value: 2, params: null }
//                    ], params: null }
// }

encodeDict

// `a=10, b=20, c=30`
encodeDict({
  a: 10,
  b: 20,
  c: 30,
})

// `a=10, b=20, c=30`
encodeDict(new Map([
                     ['a', 10],
                     ['b', 20],
                     ['c', 30],
                   ])
),


// `a=x, b="y", c=10, d=?0, e=:AQID:, f=(10 20)`
encodeDict({
  a: Symbol.for('x'),
  b: 'y',
  c: 10,
  d: false,
  e: new Uint8Array([1,2,3]),
  f: [10, 20],
})

// `a=x;a, b="y";b=10, c=10;c="test", d=?0, e=(1 2)`
encodeDict({
  a: new Item(Symbol.for('x'), {a: true}),
  b: new Item('y',             {b: 10}),
  c: new Item(10,              {c: "test"}),
  d: new Item(false),
  e: new Item([1, 2]),
})

// `a=1, b=?0, c="x", d=y, e=:AQID:`
encodeDict(new Map([
  ['a', 10],
  ['b', 20],
  ['c', 30],
])),

How to test

test includes unittest & httpwg's test.

• https://github.com/httpwg/structured-field-tests.git

you can run all test like below.

$ git submodule init && git submodule update
$ npm t