Function prepareStore

src/data/DataStore.ts:132–157

(
    store: DataValueChunk[],
    dimIdx: number,
    dimType: DataStoreDimensionType,
    end: number,
    append?: boolean
)

}

function prepareStore(
    store: DataValueChunk[],
    dimIdx: number,
    dimType: DataStoreDimensionType,
    end: number,
    append?: boolean
): void {
    const DataCtor = dataCtors[dimType || 'float'];

    if (append) {
        const oldStore = store[dimIdx];
        const oldLen = oldStore && oldStore.length;
        if (!(oldLen === end)) {
            const newStore = new DataCtor(end);
            // The cost of the copy is probably inconsiderable
            // within the initial chunkSize.
            for (let j = 0; j < oldLen; j++) {
                newStore[j] = oldStore[j];
            }
            store[dimIdx] = newStore;
        }
    }
    else {
        store[dimIdx] = new DataCtor(end);
    }
};

/**
 * Basically, DataStore API keep immutable.