Function initBreakOrLinearMapper

src/scale/scaleMapper.ts:293–329

(
    // If input `null/undefined`, a mapper will be created.
    mapper: ScaleMapper | NullUndefined,
    breakParsed: AxisBreakParsingResult | NullUndefined,
    initialExtent: number[] | NullUndefined,
)

}

export function initBreakOrLinearMapper(
    // If input `null/undefined`, a mapper will be created.
    mapper: ScaleMapper | NullUndefined,
    breakParsed: AxisBreakParsingResult | NullUndefined,
    initialExtent: number[] | NullUndefined,
): {
    // If breaks are not available, `brk` is `null/undefined`.
    brk: BreakScaleMapper | NullUndefined;
    // Never be `null/undefined`.
    mapper: ScaleMapper;
} {
    let brk: BreakScaleMapper | NullUndefined;
    mapper = mapper || {} as ScaleMapper;

    const scaleBreakHelper = getScaleBreakHelper();
    if (scaleBreakHelper) {

        const brkMapper = scaleBreakHelper.createBreakScaleMapper(breakParsed, initialExtent);

        if (brkMapper.hasBreaks()) {
            // Some `ScaleMapper` methods (such as `normalize`) needs to be fast for large data
            // when no breaks, so mount break methods only when breaks really exist.
            each(SCALE_MAPPER_METHOD_NAMES, function (methodName) {
                if (brkMapper[methodName]) {
                    (mapper as any)[methodName] = bind(brkMapper[methodName], brkMapper);
                }
            });
            brk = brkMapper;
        }
    }

    if (brk == null) {
        initLinearScaleMapper(mapper, initialExtent);
    }

    return {brk, mapper};
}

export type DecoratedScaleMapperMethods<THost extends ScaleMapper> = Omit<ScaleMapperGeneric<THost>, 'freeze'>;