Struct perspective_client::View

pub struct View {
    pub name: String,
    /* private fields */
}

Fields

name: String

Implementations

impl View

pub fn new(name: String, client: Client) -> Self

pub async fn column_paths(&self) -> ClientResult<Vec<String>>

Returns an array of strings containing the column paths of the View without any of the source columns.

A column path shows the columns that a given cell belongs to after pivots are applied.

pub async fn col_to_js_typed_array( &self, _column: &str ) -> ClientResult<Vec<u8>>

Serializes a view column into a TypedArray.

pub async fn dimensions(&self) -> ClientResult<ViewDimensionsResp>

Returns this View’s dimensions, row and column count, as well as those of the crate::Table from which it was derived.

• num_table_rows - The number of rows in the underlying crate::Table.
• num_table_columns - The number of columns in the underlying crate::Table (including the index column if this crate::Table was constructed with one).
• num_view_rows - The number of rows in this View. If this View has a group_by clause, num_view_rows will also include aggregated rows.
• num_view_columns - The number of columns in this View. If this View has a split_by clause, num_view_columns will include all column paths, e.g. the number of columns clause times the number of split_by groups.

pub async fn expression_schema( &self ) -> ClientResult<HashMap<String, ColumnType>>

The expression schema of this view, which contains only the expressions created on this view.

A schema is an Object, the keys of which are the columns of this view, and the values are their string type names. If this view is aggregated, these will be the aggregated types; otherwise these types will be the same as the columns in the underlying table.

pub async fn get_config(&self) -> ClientResult<ViewConfig>

A copy of the config object passed to the [Table::view] method which created this View.

pub async fn num_rows(&self) -> ClientResult<u32>

The number of aggregated rows in this view. This is affected by the “group_by” configuration parameter supplied to this view’s contructor.

Returns

The number of aggregated rows.

pub async fn schema(&self) -> ClientResult<HashMap<String, ColumnType>>

The schema of this view.

A schema is an Object, the keys of which are the columns of this view, and the values are their string type names. If this view is aggregated, theses will be the aggregated types; otherwise these types will be the same as the columns in the underlying table.

Examples

// Create a view
const view = await table.view({
    columns: ["a", "b"],
});
const schema = await view.schema(); // {a: "float", b: "string"}

pub async fn to_arrow(&self, window: ViewWindow) -> ClientResult<Vec<u8>>

Serializes a view to the Apache Arrow data format.

pub async fn to_columns_string( &self, window: ViewWindow ) -> ClientResult<String>

Serializes this view to a string of JSON data. Useful if you want to save additional round trip serialize/deserialize cycles.

pub async fn to_json_string(&self, window: ViewWindow) -> ClientResult<String>

pub async fn to_csv(&self, window: ViewWindow) -> ClientResult<String>

Serializes this view to CSV data in a standard format.

pub async fn delete(&self) -> ClientResult<()>

Delete this View and clean up all resources associated with it. View objects do not stop consuming resources or processing updates when they are garbage collected - you must call this method to reclaim these.

pub async fn get_min_max( &self, column_name: String ) -> ClientResult<(String, String)>

Calculates the [min, max] of the leaf nodes of a column column_name.

Returns

A tuple of [min, max], whose types are column and aggregate dependent.

pub async fn on_update( &self, on_update: Box<dyn Fn(OnUpdateArgs) + Send + Sync + 'static>, options: OnUpdateOptions ) -> ClientResult<u32>

Register a callback with this View. Whenever the view’s underlying table emits an update, this callback will be invoked with an object containing port_id, indicating which port the update fired on, and optionally delta, which is the new data that was updated for each cell or each row.

Arguments

• on_update - A callback function invoked on update, which receives an object with two keys: port_id, indicating which port the update was triggered on, and delta, whose value is dependent on the mode parameter.
• options - If this is provided as OnUpdateOptions { mode: Some(OnUpdateMode::Row) }, then delta is an Arrow of the updated rows. Otherwise delta will be Option::None.

Examples

// Attach an `on_update` callback
view.on_update((updated) => console.log(updated.port_id));

// `on_update` with row deltas
view.on_update((updated) => console.log(updated.delta), { mode: "row" });

pub async fn remove_update(&self, update_id: u32) -> ClientResult<()>

Unregister a previously registered update callback with this view.

Example

// remove an `on_update` callback
const callback = () => console.log("Updated!");
view.remove_update(callback);

pub async fn on_delete( &self, on_delete: Box<dyn Fn() + Send + Sync + 'static> ) -> ClientResult<u32>

Register a callback with this view. Whenever the view is deleted, this callback will be invoked.

Example

// attach an `on_delete` callback
view.on_delete(() => console.log("Deleted!"));

pub async fn remove_delete(&self, callback_id: u32) -> ClientResult<()>

Unregister a previously registered delete callback with this view.

Example

// remove an `on_delete` callback
const callback = () => console.log("Deleted!");
view.remove_delete(callback);

pub async fn collapse(&self, row_index: i32) -> ClientResult<i64>

Collapses the row at index row_index.

This is used during a pivot.

Examples

// make table
// make view with pivot
// collapse a row.

pub async fn expand(&self, row_index: i32) -> ClientResult<i64>

Expands the row at index row_index.

This is used during a pivot.

Examples

// make table
// make view with pivot
// expand a row.

pub async fn set_depth(&self, depth: i32) -> ClientResult<()>

Set expansion depth of the pivot tree.

Trait Implementations

impl Clone for View

fn clone(&self) -> View

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for View

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.