the main structure

Property Relationships

Class diagram image-center

‘MetaTable’ is similar to the structure and usage of the ‘DataTable’ class in the .NET framework

an inheritance relationship

Class diagram image-center

a key element

Properties

Item Description
tableName This property represents the name of the table
columns contains all columns in the item (attribute) collection table for this entity
rows Data (low) collection of entities
_metaSet MetaSet to which the entity belongs.
_guid Unique identifier of the object (GUID). Uniquely identifies the object.
_type The generator function of the object. The function used when the object was created.
   

Method

Item Description
clone() Create and return a deep copy of the current object
copy(filter, args) Copy the destination column
acceptChanges() Commit all changes to the current object. Allow changes: commit
rejectChanges() Rollback all changes to the current object. Cancel changes: rollback
getChanges() Returns a list of changes to the current object
transformSchema() Converts a given serialization object to a schema object
Clear() Initializes all data in the entity
reset() Initializes the entity’s columns and data
NewRow() Returns a new row that matches the column structure
getValue() Returns the value of the column as a MetaRow type object
setValue(row) Set the MetaRow value to the value of the column
merge (target, optoin, matchType) merge the given entity with the current entity
select(filter, args) query the row according to the given callback function
load(obj, path) Gets the given object into the current entity. Initializes the existing data and loads the new data
output (Vopt, stringify, space) Outputs the current entity as a serialized string
read(obj, option) Reads the given object as an entity. Follow JSON schema rules.
readSchema (obj, createRow) Reads the given schema object as the current entity
readData(obj) Reads only rows that exist on a given object
write(vOpt) Returns the current entity by converting it to an object of schema type
writeSchema(vOpt) Returns the schema of the current entity by converting it to an object of schema type
writeData(vOpt) Returns data from the current entity by converting it into schema-type objects.

Detailed description

Key Properties

tableName

Indicates the name of the table.

type tableName = string;

columns

Collection of columns in the table.

type columns = MetaTableColumnCollection;

rows

Data (low) collection of tables.

type rows = MetaRowCollection;

_metaSet

This is the meta set to which the table belongs.

type _metaSet = MetaSet;

_guid

Unique identifier of the object (GUID). Uniquely identifies the object.

type _guid = string;

_type

The generator function of the object, which was used when the object was created.

type _type = Function;

Key Methods

clone()

Create and return a deep copy of the current object.

type clone = () => MetaTable;
  • return : This is a replica of the current object.

copy()

Copy the target column.

type copy = (
    filter: (row, idx, entity) => boolean | string[], arguments<string>, 
    cols?: string[] | arguments<string>
) => MetaTable;
  • filter :
    • Function type is the callback function that selects the column.
    • Type string[] is the name of the column to copy.
  • cols : The name of the column to copy, valid only if the filter is a Function type.

Example: Using filter, cols

var table = new MetaTable('t1');

// ... Add columns, aa, bb, cc, e, and rows 

var temp = table.copy(
    (row, idx, entity) => { return (idx % 2) > 0; },
    ['aa', 'bb']
);
  • Temp is copied only if the row indexes of the columns ‘aa’ and ‘bbb’ are odd.

Example: Using cols only

var table = new MetaTable('t1');

// ... Add columns, aa, bb, cc, e, and rows 

var temp = table.copy(
    ['aa', 'bb']
);
  • Temp copies the entire row of columns ‘aa’ and ‘bbb’.

acceptChanges()

Commit all changes to the current object. Allow changes: commit

type acceptChanges = () => void;

rejectChanges()

Rolls back all changes to the current object. Cancel changes: rollback

type rejectChanges = () => void;

getChanges()

Returns a list of changes to the current object.

type getChanges = () => object[];
  • return : This is the changed list.

    transformSchema()

Converts a given serialization object to a schema object.

type transformSchema = (oGuid: object) => object; // static
  • oGuid : object obtained by getObject().

clear()

Initializes all data in the entity.

type clear = () => void;

reset()

Initializes the entity’s columns and data.

type reset = () => void;

newRow()

Create and return a new row that matches the column structure.

type newRow = () => MetaRow;
  • return : This is the MetaRow object created.

    getValue()

Returns the value of the > column as a MetaRow type object.

type getValue = () => MetaRow;
  • return : MetaRow object with the value of the column set.

setValue()

Set the MetaRow value to the value in the column.

type setValue = (row: MetaRow) => void;
  • row : MetaRow object to be set.

merge()

Merges the given entity with the current entity.

type merge = (target: BaseEntity, option: number, matchType?: boolean) => void;
  • target : The target entity to merge.
  • option : Merge option.
  • matchType : Whether or not a row validation exists. (Default: false)

select()

Look up the row according to the given callback function.

type select = (
    filter: (row, idx, entity) => boolean | string[], | arguments<string>,
    cols?: string[] | arguments<string>
) => MetaView;
  • filter :
    • Function type is the callback function that selects the column.
    • Type string[] is the name of the column to copy.
  • cols : The name of the column to copy, valid only if the filter is a Function type.

Example: Using filter, cols

var table = new MetaTable('t1');

// ... Add columns, aa, bb, cc, e, and rows
var temp = table.copy(
    (row, idx, entity) => { return (idx % 2) > 0; },
    ['aa', 'bb']
);
  • The temp view is copied only if the row indexes of the columns ‘aa’, ‘bbb’ are odd.

Example: Using cols only

var table = new MetaTable('t1');

// ... Add columns, aa, bb, cc, e, and rows 

var temp = table.copy(
    ['aa', 'bb']
);
  • The temp view copies the entire row of columns ‘aa’ and ‘bbb’.

load()

Imports the given object to the current entity, initializes the existing data and loads the new data.

type load = (obj: object | string, parse?: Function) => void;
  • obj : The object to be called.
  • pas : parser function. (Optional)

output()

Outputs the current entity as a serialized string.

type output = (vOpt: number, stringify?: Function, space?: string) => string;
  • vOpt : Optional (0, 1, 2)
  • stringify : This is a user-defined parser function. (Optional)
  • space : A blank string to be used in the output. (Optional)

read()

Reads the given object as an entity. Follow JSON schema rules.

type read = (obj: object, option: number) => void;
  • obj : object to be read.
  • option : Read option (default: 3)
var schema1 = { 
    table: { 
        columns: {}, 
        rows: {} 
    }
};

var schema1 = { 
    columns: {...}, 
    rows: {} 
};

readSchema()

Reads the given schema object as the current entity.

type readSchema = (obj: object, createRow?: boolean) => void;
  • obj : Schema object to be read.
  • createRow : If true, add the column by row[0] (default: false)

readData()

Reads only rows that exist on a given object.

type readData = (obj: object) => void;
  • obj : The object to be read.

write()

Returns the current entity after converting it to an object of schema type.

type write = (vOpt?: number) => object;
  • vOpt : Optional (default: 0)
  • return : Object of schema type.

writeSchema()

Returns the schema of the current entity by converting it to an object of schema type.

type writeData = (vOpt?: number): object;
  • vOpt : Optional (default: 0)
  • return : Object of schema type.

writeData()

Returns the data of the current entity by converting it into an object of schema type.

type writeData = (vOpt?: number) => object;
  • vOpt : Optional (default: 0)
  • return : Object of schema type.

getObject()

Obtain the current object as a guide type object. (Circular references are replaced by $ref values.)

type getObject = (vOpt?: number, owned?: object | Array<object>) => object;
  • vOpt : Import option; default is 0.
    • opt=0: Reference structure (_guid:Yes, $ref:Yes)
    • opt=1: Redundant structure (_guid:Yes, $ref:Yes)
    • opt=2 : Non-tidal structure (_guid: No, $ref: No)
  • aged : The parent objects that currently own the object. The default is an empty object.
  • return —Returns serialized objects.
a.getObject(2) == b.getObject(2)

setObject()

Set the Guid type object to the current object. (The object will be reset.)

type setObject = (oGuid: object, origin?: object) => void;
  • oGuid : Object of the guid type to serialize.
  • origin : This is the original object that sets the current object. The default is oGuid.

equal()

Compare the current object with the specified object.

type equal = (target: object) => boolean;
  • return —Returns whether the two objects are identical.

getTypes()

Returns the creators of the current object and all the creators of the prototype chain to the array.

type getTypes = () => Array<Function>;
  • return : Returns the array of generator functions.
const types = obj.getTypes();
console.log(types); // [Function: MetaObject]

instanceOf()

Verify that the current object is an instance of the specified type (including _UNION)

type instanceOf = (target: object | string) => boolean;
  • target : The type of object to be checked (object or string).
  • return —Returns whether this is an instance of the specified type.

Updated: