Add a column search interface to handle search values

This will hold the object keys as properties, and strings as their
values. This may not be the best way to implement it, because the
interface just has an [index signature][1] for the column names, but it
seems to work for now. Hopefully there just get referenced by objectKey.

[1]: https://www.typescriptlang.org/docs/handbook/interfaces.html#excess-property-checks

Author: mklein994

@angular-generic-table/core/components/generic-table.component.ts

@@ -40,8 +40,9 @@ import { GtEvent } from '../interfaces/gt-event';
                                                 [injector]="(gtFields | gtProperty:column.objectKey:'header')?.injector"
                                                 [column]="gtFields | gtProperty:column.objectKey:'name'"></gt-custom-component-factory>
                     <!-- don't trigger a sort when clicking on the search box -->
-                    <input *ngIf="gtSettings | gtProperty:column.objectKey:'searchBox'"
+                    <input #columnSearch *ngIf="gtSettings | gtProperty:column.objectKey:'searchBox'"
                       (click)="$event.stopPropagation()"
+                      (keyup)="gtColumnSearch(column.objectKey, columnSearch.value)"
                       type="text"
                       placeholder="Filter by {{gtFields | gtProperty:column.objectKey:'name' | lowercase}}" />
                     <gt-checkbox *ngIf="(gtFields | gtProperty:column.objectKey:'columnComponent')?.type === 'checkbox'" [checked]="(selectedRows.length === gtData.length)" (changed)="(selectedRows.length !== gtData.length) ? selectAllRows() : deselectAllRows();"></gt-checkbox>
@@ -252,6 +253,10 @@ export class GenericTableComponent<R extends GtRow, C extends GtExpandedRow<R>>
 					COLUMNS_WITH_CLASS_NAMES[0].objectKey
 			);
 		}
+
+		this._gtFields.forEach(field => {
+			this.gtInfo.columnSearchTerms[field.objectKey] = '';
+		});
 	}
 	@Input()
 	set gtSettings(value: GtConfigSetting[]) {
@@ -411,7 +416,8 @@ export class GenericTableComponent<R extends GtRow, C extends GtExpandedRow<R>>
 		recordLength: this.gtOptions.numberOfRows,
 		recordsAll: 0,
 		recordsAfterFilter: 0,
-		recordsAfterSearch: 0
+		recordsAfterSearch: 0,
+		columnSearchTerms: {}
 	};
 
 	public refreshPipe = false;
@@ -1236,6 +1242,11 @@ export class GenericTableComponent<R extends GtRow, C extends GtExpandedRow<R>>
 		this.updateTotals();
 	}
 
+	public gtColumnSearch(objectKey: number, value: string) {
+		// map the column search value to its column
+		this.gtInfo.columnSearchTerms[objectKey] = value;
+	}
+
 	/**
 	 * Add rows
 	 * @param rows - rows to add

@angular-generic-table/core/interfaces/gt-column-search.ts

@@ -0,0 +1,6 @@
+export interface GtColumnSearch {
+	/**
+	 * Column name with its search value.
+	 */
+	[columnName: string]: string;
+}

@angular-generic-table/core/interfaces/gt-information.ts

@@ -1,3 +1,5 @@
+import { GtColumnSearch } from '../interfaces/gt-column-search';
+
 export interface GtInformation {
 	filter?: Object;
 	pageCurrent: number;
@@ -11,5 +13,6 @@ export interface GtInformation {
 	recordsAfterFilter: number;
 	recordsAfterSearch: number;
 	searchTerms?: string;
+	columnSearchTerms?: GtColumnSearch;
 	visibleRecords?: any;
 }