Class ChartBuilder

Fluent wrapper around an RpeJson object.

All mutating methods return this for chaining. Use .data to access the underlying raw chart at any time.

Factory methods

ChartBuilder.empty(bpm?, name?) — create a new chart
ChartBuilder.from(chart) — wrap an existing RpeJson

Methods summary

Category	Methods
Lines	`.line()`, `.lines()`, `.getLine()`, `.removeLine()`, `.duplicateLine()`
BPM	`.bpm()`, `.setBpm()`, `.removeBpm()`
Transforms	`.offset()`, `.mirror()`, `.merge()`
Metadata	`.setName()`, `.setCharter()`, `.setComposer()`, `.setLevel()`, `.setOffset()`, `.setBackground()`, `.setSong()`
Iterators	`.notes()`, `.lineIterator()`, `.events()`
Stats	`.stats()`, `.validate()`, `.serialize()`

Example

const chart = ChartBuilder.empty(120, 'My Chart')
  .setCharter('Me')
  .bpm(16, 140)      // tempo change at beat 16
  .offset(8);        // shift everything 8 beats forward

const line = chart.line({ name: 'Main' });
line.moveX(0, 4, 0, 675, 'cubicOut').addNote(2);

const json = chart.data; // access raw RpeJson

Index

Constructors

constructor

new ChartBuilder(data: RpeJson): ChartBuilder
Parameters
- data: RpeJson
Returns ChartBuilder
- Defined in prototype.ts:158

Properties

`Readonly`data

data: RpeJson

The underlying chart data. Direct mutations are fine.

Accessors

lineCount

get lineCount(): number
Number of lines in the chart.

Returns number
- Defined in prototype.ts:362

Methods

`Static`from

from(chart: RpeJson): ChartBuilder
Wrap an existing chart object.
Parameters
- chart: RpeJson
Returns ChartBuilder
- Defined in prototype.ts:166

`Static`empty

empty(bpm?: number, name?: string): ChartBuilder
Create a new empty chart and wrap it.
Parameters
- bpm: number = 120
  Initial BPM (default: 120).
- name: string = "Untitled"
  Chart name (default: 'Untitled').
Returns ChartBuilder
- Defined in prototype.ts:175

line

line(options?: CreateLineOptions, createDefaultEvents?: boolean): LineBuilder
Add a new line and return its LineBuilder. The ChartBuilder is accessible via lineBuilder.chart.
Parameters
- options: CreateLineOptions = {}
- createDefaultEvents: boolean = true
Returns LineBuilder
- Defined in prototype.ts:185

getLine

getLine(index: number): LineBuilder
Get a LineBuilder for an existing line at index.
Parameters
- index: number
Returns LineBuilder
- Defined in prototype.ts:193

lines

lines(
    count: number,
    options?: CreateLineOptions | ((i: number) => CreateLineOptions),
    createDefaultEvents?: boolean,
): LineBuilder[]
Add multiple lines at once, returning an array of LineBuilders.
Parameters
- count: number
- options: CreateLineOptions | ((i: number) => CreateLineOptions) = {}
- createDefaultEvents: boolean = true
Returns LineBuilder[]
- Defined in prototype.ts:203

removeLine

removeLine(index: number): this
Remove a line by index. Updates parent references automatically.
Parameters
- index: number
Returns this
- Defined in prototype.ts:216

removeBpm

removeBpm(index: number): this
Remove a BPM change at the given index (cannot remove index 0).
Parameters
- index: number
Returns this
- Defined in prototype.ts:224

duplicateLine

duplicateLine(index: number, includeNotes?: boolean): LineBuilder
Duplicate a line by index and return the new LineBuilder.
Parameters
- index: number
- includeNotes: boolean = true
Returns LineBuilder
- Defined in prototype.ts:232

setBpm

setBpm(bpm: number): this
Set the chart to a single constant BPM, replacing all existing BPM entries.
Parameters
- bpm: number
Returns this
- Defined in prototype.ts:242

bpm

bpm(beat: number, bpm: number): this
Add a BPM change at beat.
Parameters
- beat: number
- bpm: number
Returns this
- Defined in prototype.ts:250

offset

offset(beatOffset: number): this
Offset the entire chart by beatOffset beats.
Parameters
- beatOffset: number
Returns this
- Defined in prototype.ts:260

mirror

mirror(): this
Mirror the entire chart horizontally.

Returns this
- Defined in prototype.ts:268

merge

merge(source: RpeJson | ChartBuilder): this
Merge all lines from source into this chart.
Parameters
- source: RpeJson | ChartBuilder
Returns this
- Defined in prototype.ts:276

notes

notes(): NoteIterator
Create a NoteIterator pre-scoped to this chart's notes.

Returns NoteIterator
- Defined in prototype.ts:284

lineIterator

lineIterator(): LineIterator
Create a LineIterator pre-scoped to this chart.

Returns LineIterator
- Defined in prototype.ts:289

events

events(): EventIterator
Create an EventIterator pre-scoped to this chart.

Returns EventIterator
- Defined in prototype.ts:294

setName

setName(name: string): this
Set the chart name.
Parameters
- name: string
Returns this
- Defined in prototype.ts:301

setOffset

setOffset(offsetMs: number): this
Set the chart offset (in milliseconds).
Parameters
- offsetMs: number
Returns this
- Defined in prototype.ts:307

setLevel

setLevel(level: string): this
Set the level string (e.g. 'SP Lv.15').
Parameters
- level: string
Returns this
- Defined in prototype.ts:313

setCharter

setCharter(charter: string): this
Set the charter (chart author) name.
Parameters
- charter: string
Returns this
- Defined in prototype.ts:319

setComposer

setComposer(composer: string): this
Set the composer name.
Parameters
- composer: string
Returns this
- Defined in prototype.ts:325

setBackground

setBackground(background: string): this
Set the background image path.
Parameters
- background: string
Returns this
- Defined in prototype.ts:331

setSong

setSong(song: string): this
Set the song audio file path.
Parameters
- song: string
Returns this
- Defined in prototype.ts:337

stats

stats(): ChartStats
Compute summary statistics for the chart.

Returns ChartStats
- Defined in prototype.ts:345

validate

validate(): ValidationIssue[]
Validate the chart and return any issues found.

Returns ValidationIssue[]
- Defined in prototype.ts:350

serialize

serialize(pretty?: boolean): string
Serialize the chart to a JSON string.
Parameters
- pretty: boolean = true
Returns string
- Defined in prototype.ts:357

rawLine

rawLine(index: number): JudgeLine
Get the judge line object at index directly.
Parameters
- index: number
Returns JudgeLine
- Defined in prototype.ts:367

addLine

addLine(options?: CreateLineOptions, createDefaultEvents?: boolean): LineBuilder
Add a new line and return its LineBuilder. Alias for .line().
Parameters
- options: CreateLineOptions = {}
- createDefaultEvents: boolean = true
Returns LineBuilder
- Defined in prototype.ts:379

addBpmChange

addBpmChange(beat: number, bpm: number): this
Add a BPM change at beat. Alias for .bpm(beat, bpm).
Parameters
- beat: number
- bpm: number
Returns this
- Defined in prototype.ts:387

Class ChartBuilder

Factory methods

Methods summary

Example

Index

Constructors

Properties

Accessors

Methods

Constructors

constructor

Parameters

Returns ChartBuilder

Properties

Readonlydata

Accessors

lineCount

Returns number

Methods

Staticfrom

Parameters

Returns ChartBuilder

Staticempty

Parameters

Returns ChartBuilder

line

Parameters

Returns LineBuilder

getLine

Parameters

Returns LineBuilder

lines

Parameters

Returns LineBuilder[]

removeLine

Parameters

Returns this

removeBpm

Parameters

Returns this

duplicateLine

Parameters

Returns LineBuilder

setBpm

Parameters

Returns this

bpm

Parameters

Returns this

offset

Parameters

Returns this

mirror

Returns this

merge

Parameters

Returns this

notes

Returns NoteIterator

lineIterator

Returns LineIterator

events

Returns EventIterator

setName

Parameters

Returns this

setOffset

Parameters

Returns this

setLevel

Parameters

Returns this

setCharter

Parameters

Returns this

setComposer

Parameters

Returns this

setBackground

Parameters

`Readonly`data

`Static`from

`Static`empty