Sintaks YAML Referensi

Referensi sintaks YAML 1.2 lengkap dengan contoh. Mencakup skalar, urutan, pemetaan, jangkar, string multi-baris, tag, dan jebakan umum.

Dasar & Skalar

String (unquoted)⚠ Avoid starting with special chars

Plain unquoted string — most common

name: John Doe

String (single quotes)⚠ Single quote inside: escape as ''

Single-quoted: no variable or escape processing

path: '/usr/bin/node'

String (double quotes)⚠ Required for special characters

Double-quoted: supports escape sequences (\n, \t, etc.)

message: "Hello\nWorld"

Integer

Whole number (base 10)

port: 8080

Float

Floating point number

threshold: 0.95

Boolean (true/false)⚠ YAML 1.1: yes/no/on/off also work — avoid!

Boolean value — use only true/false (YAML 1.2)

debug: false

Null⚠ Also: ~ or empty value

Null / absence of value

response: null

Date⚠ Parsed as date by most YAML parsers

ISO 8601 date format

created: 2024-01-15T10:30:00Z

Comment

Single-line comment. No multi-line comment syntax.

# This is a comment
key: value  # inline comment

Explicit type tag

Force value to be treated as a specific type

port: !!str 8080  # string '8080' not int

Koleksi

Mapping (block)

Key-value pairs — indented block style

app:
  name: myapp
  port: 3000

Mapping (flow/inline)

Inline map — equivalent to block style

env: {NODE_ENV: prod, PORT: 8080}

Sequence (block)

List of items — block style with dash+space

fruits:
  - apple
  - banana
  - cherry

Sequence (flow/inline)

Inline list — equivalent to block style

ports: [80, 443, 8080]

Sequence of mappings

List where each item is a map

users:
  - name: Alice
    role: admin
  - name: Bob
    role: user

Nested mappings

Arbitrarily deep nesting

database:
  primary:
    host: db1.example.com
    port: 5432

Merge key (<<)

Merge the keys of a referenced mapping into current map

defaults: &defaults
  color: blue
button:
  <<: *defaults
  text: Submit

String Multi-baris

Literal block (|)⚠ Trailing newline added by default

Preserves newlines exactly as written

script: |
  #!/bin/bash
  echo "hello"
  exit 0

Folded block (>)⚠ Blank lines become newlines

Newlines folded into spaces (great for long descriptions)

description: >
  This is a very long
  description that will
  be joined into one line.

Strip chomping (|-)

Literal block, strip all trailing newlines

prompt: |-
  Enter value:

Keep chomping (|+)

Literal block, keep all trailing newlines

template: |+
  line1

Folded strip (>-)

Folded block, strip trailing newlines

message: >-
  This folds into
  one line no trailing newline

Jangkar & Alias

Define anchor (&)

Assigns an anchor (label) to the current node

base: &base
  image: node:18
  restart: always

Reference alias (*)

References (copies) an anchored node

service1:
  <<: *base
  name: api
service2:
  <<: *base
  name: worker

Anchor a scalar

Anchor a scalar value to reuse it

read_timeout: &rto 30
write_timeout: *rto
connect_timeout: *rto

Anchor a sequence

Anchor a list

primary_colors: &colors
  - red
  - blue
text_colors: *colors

Lanjutan & Tag

Directive (YAML version)

Explicitly declare YAML version (optional, rarely needed)

%YAML 1.2
---
name: myapp

Document start (---)

Marks the start of a YAML document. Required if using directives.

---
kind: Deployment
---
kind: Service

Document end (...)

Marks the end of a YAML document. Optional but useful.

---
debug: true
...

Multiple documents

Multiple YAML docs in one file (stream)

Used in Kubernetes multi-resource files

Binary tag (!!binary)

Base64-encoded binary data

icon: !!binary |
  iVBORw0KGgo=

Jebakan Umum

Tabs NOT allowed⚠ Configure your editor to convert tabs to spaces

Indentation MUST use spaces only — never tabs

# WRONG:
parent:
\tchild: value
# RIGHT:
parent:
  child: value

Colon in value needs quotes

Values containing ': ' (colon+space) must be quoted

# WRONG:
url: http://example.com
# RIGHT:
url: "http://example.com"

Numbers as strings

1.0 parses as float! Quote or tag it to keep as string

version: '1.0'  # string
version: 1.0    # float

yes/no/on/off as booleans

YAML 1.1 parses yes/no/on/off as booleans — quote to use strings

# YAML 1.1 (PyYAML):
on: true    # 'on' is boolean true!
# Safe: always quote
on: 'on'

Trailing spaces matter

Trailing spaces in keys are included in the key string

"key " (with space) != "key" — trim carefully

Duplicate keys

Duplicate keys — behavior is parser-specific (usually last wins). Treat as error.

Use a YAML linter to detect duplicate keys

YAML vs JSON: Perbedaan Utama

Fitur	YAML	JSON
Komentar	Yes: # comment	Tidak didukung
Tanda kutip diperlukan	Opsional untuk string	Diperlukan untuk string
Anchors/aliases	Yes: &anchor / *alias	Tidak didukung
String multi-baris	Yes: \| and > blocks	Escaped \n only
Tab untuk indentasi	Hanya spasi	Keduanya
Merupakan superset dari JSON	Semua JSON adalah YAML yang valid	-
Keterbacaan manusia	Sangat tinggi	Sedang
Ketersediaan parser	Tinggi	Sangat tinggi

YAML 1.1 vs YAML 1.2 - Apa yang Berubah?

Penting: Banyak parser YAML masih menggunakan YAML 1.1 secara default (PyYAML Python, Psych Ruby dalam beberapa versi).

YAML 1.1 (parser lama)

yes / no -> boolean
on / off -> boolean
true / false -> boolean
0755 -> octal integer
1_000 -> integer (1000)

YAML 1.2 (standar modern)

true / false only as booleans
yes / no -> plain strings
on / off -> plain strings
0o755 -> octal (0755 is int)
Integers: no underscore separator

Pertanyaan yang Sering Diajukan

Apa perbedaan antara YAML dan JSON?

YAML adalah superset dari JSON — setiap JSON yang valid adalah YAML yang valid. YAML dirancang untuk lebih mudah dibaca manusia dengan dukungan komentar, string multi-baris, dan anchors/aliases. JSON lebih ketat, lebih cepat diurai, dan didukung secara universal. Gunakan YAML untuk file konfigurasi dan JSON untuk API dan pertukaran data.

Mengapa YAML memperlakukan 'on', 'off', 'yes', 'no' sebagai boolean?

Dalam YAML 1.1 (digunakan oleh banyak parser termasuk PyYAML), 'on', 'off', 'yes', 'no' adalah nilai boolean yang valid. Ini dapat menyebabkan bug ketika digunakan sebagai string biasa (mis., di Ansible). YAML 1.2 memperbaiki ini — hanya 'true' dan 'false' yang merupakan boolean. Solusi: selalu beri tanda kutip pada nilai-nilai ini ('yes', 'no') jika ingin menggunakannya sebagai string.

Bagaimana cara merepresentasikan string multi-baris di YAML?

Gunakan literal block scalar (|) untuk mempertahankan baris baru: setiap baris dalam blok menjadi baris baru yang sebenarnya dalam string. Gunakan folded block scalar (>) untuk mengubah baris baru menjadi spasi: ideal untuk paragraf panjang. Keduanya mendukung indikator chomping opsional (- untuk menghapus baris baru di akhir, + untuk mempertahankan semuanya).

Apa yang menyebabkan 'kesalahan indentasi YAML'?

YAML menggunakan spasi untuk indentasi — tidak pernah tab. Semua kunci saudara harus berada pada level indentasi yang sama. Mencampur tab dan spasi akan selalu menyebabkan kesalahan. Perbaikan umum: aktifkan pengaturan 'ganti tab dengan spasi' di editor Anda, gunakan linter (yamllint), pastikan lebar indentasi konsisten (2 atau 4 spasi) di seluruh file.

Dasar & Skalar

String (unquoted)⚠ Avoid starting with special chars

Plain unquoted string — most common

name: John Doe

String (single quotes)⚠ Single quote inside: escape as ''

Single-quoted: no variable or escape processing

path: '/usr/bin/node'

String (double quotes)⚠ Required for special characters

Double-quoted: supports escape sequences (\n, \t, etc.)

message: "Hello\nWorld"

Integer

Whole number (base 10)

port: 8080

Float

Floating point number

threshold: 0.95

Boolean (true/false)⚠ YAML 1.1: yes/no/on/off also work — avoid!

Boolean value — use only true/false (YAML 1.2)

debug: false

Null⚠ Also: ~ or empty value

Null / absence of value

response: null

Date⚠ Parsed as date by most YAML parsers

ISO 8601 date format

created: 2024-01-15T10:30:00Z

Comment

Single-line comment. No multi-line comment syntax.

# This is a comment
key: value  # inline comment

Explicit type tag

Force value to be treated as a specific type

port: !!str 8080  # string '8080' not int

Koleksi

Mapping (block)

Key-value pairs — indented block style

app:
  name: myapp
  port: 3000

Mapping (flow/inline)

Inline map — equivalent to block style

env: {NODE_ENV: prod, PORT: 8080}

Sequence (block)

List of items — block style with dash+space

fruits:
  - apple
  - banana
  - cherry

Sequence (flow/inline)

Inline list — equivalent to block style

ports: [80, 443, 8080]

Sequence of mappings

List where each item is a map

users:
  - name: Alice
    role: admin
  - name: Bob
    role: user

Nested mappings

Arbitrarily deep nesting

database:
  primary:
    host: db1.example.com
    port: 5432

Merge key (<<)

Merge the keys of a referenced mapping into current map

defaults: &defaults
  color: blue
button:
  <<: *defaults
  text: Submit

String Multi-baris

Literal block (|)⚠ Trailing newline added by default

Preserves newlines exactly as written

script: |
  #!/bin/bash
  echo "hello"
  exit 0

Folded block (>)⚠ Blank lines become newlines

Newlines folded into spaces (great for long descriptions)

description: >
  This is a very long
  description that will
  be joined into one line.

Strip chomping (|-)

Literal block, strip all trailing newlines

prompt: |-
  Enter value:

Keep chomping (|+)

Literal block, keep all trailing newlines

template: |+
  line1

Folded strip (>-)

Folded block, strip trailing newlines

message: >-
  This folds into
  one line no trailing newline

Jangkar & Alias

Define anchor (&)

Assigns an anchor (label) to the current node

base: &base
  image: node:18
  restart: always

Reference alias (*)

References (copies) an anchored node

service1:
  <<: *base
  name: api
service2:
  <<: *base
  name: worker

Anchor a scalar

Anchor a scalar value to reuse it

read_timeout: &rto 30
write_timeout: *rto
connect_timeout: *rto

Anchor a sequence

Anchor a list

primary_colors: &colors
  - red
  - blue
text_colors: *colors

Lanjutan & Tag

Directive (YAML version)

Explicitly declare YAML version (optional, rarely needed)

%YAML 1.2
---
name: myapp

Document start (---)

Marks the start of a YAML document. Required if using directives.

---
kind: Deployment
---
kind: Service

Document end (...)

Marks the end of a YAML document. Optional but useful.

---
debug: true
...

Multiple documents

Multiple YAML docs in one file (stream)

Used in Kubernetes multi-resource files

Binary tag (!!binary)

Base64-encoded binary data

icon: !!binary |
  iVBORw0KGgo=

Jebakan Umum

Tabs NOT allowed⚠ Configure your editor to convert tabs to spaces

Indentation MUST use spaces only — never tabs

# WRONG:
parent:
\tchild: value
# RIGHT:
parent:
  child: value

Colon in value needs quotes

Values containing ': ' (colon+space) must be quoted

# WRONG:
url: http://example.com
# RIGHT:
url: "http://example.com"

Numbers as strings

1.0 parses as float! Quote or tag it to keep as string

version: '1.0'  # string
version: 1.0    # float

yes/no/on/off as booleans

YAML 1.1 parses yes/no/on/off as booleans — quote to use strings

# YAML 1.1 (PyYAML):
on: true    # 'on' is boolean true!
# Safe: always quote
on: 'on'

Trailing spaces matter

Trailing spaces in keys are included in the key string

"key " (with space) != "key" — trim carefully

Duplicate keys

Duplicate keys — behavior is parser-specific (usually last wins). Treat as error.

Use a YAML linter to detect duplicate keys

YAML vs JSON: Perbedaan Utama

Fitur	YAML	JSON
Komentar	Yes: # comment	Tidak didukung
Tanda kutip diperlukan	Opsional untuk string	Diperlukan untuk string
Anchors/aliases	Yes: &anchor / *alias	Tidak didukung
String multi-baris	Yes: \| and > blocks	Escaped \n only
Tab untuk indentasi	Hanya spasi	Keduanya
Merupakan superset dari JSON	Semua JSON adalah YAML yang valid	-
Keterbacaan manusia	Sangat tinggi	Sedang
Ketersediaan parser	Tinggi	Sangat tinggi

YAML 1.1 vs YAML 1.2 - Apa yang Berubah?

Penting: Banyak parser YAML masih menggunakan YAML 1.1 secara default (PyYAML Python, Psych Ruby dalam beberapa versi).

YAML 1.1 (parser lama)

yes / no -> boolean
on / off -> boolean
true / false -> boolean
0755 -> octal integer
1_000 -> integer (1000)

YAML 1.2 (standar modern)

true / false only as booleans
yes / no -> plain strings
on / off -> plain strings
0o755 -> octal (0755 is int)
Integers: no underscore separator

Sintaks YAML Referensi

Dasar & Skalar

Koleksi

String Multi-baris

Jangkar & Alias

Lanjutan & Tag

Jebakan Umum

YAML vs JSON: Perbedaan Utama

YAML 1.1 vs YAML 1.2 - Apa yang Berubah?

YAML 1.1 (parser lama)

YAML 1.2 (standar modern)

Pertanyaan yang Sering Diajukan

Apa perbedaan antara YAML dan JSON?

Mengapa YAML memperlakukan 'on', 'off', 'yes', 'no' sebagai boolean?

Bagaimana cara merepresentasikan string multi-baris di YAML?

Apa yang menyebabkan 'kesalahan indentasi YAML'?

YAML tools

Sintaks YAML Referensi

Dasar & Skalar

Koleksi

String Multi-baris

Jangkar & Alias

Lanjutan & Tag

Jebakan Umum

YAML vs JSON: Perbedaan Utama

YAML 1.1 vs YAML 1.2 - Apa yang Berubah?

YAML 1.1 (parser lama)

YAML 1.2 (standar modern)

Pertanyaan yang Sering Diajukan

Apa perbedaan antara YAML dan JSON?

Mengapa YAML memperlakukan 'on', 'off', 'yes', 'no' sebagai boolean?

Bagaimana cara merepresentasikan string multi-baris di YAML?

Apa yang menyebabkan 'kesalahan indentasi YAML'?