igniteui-angular-sovn/src/lib/grids/watch-changes.ts

Ignite UI for Angular is a dependency-free Angular toolkit for building modern web apps

import { SimpleChanges, SimpleChange } from '@angular/core';

/**
 * @hidden
 */
export function WatchChanges(): PropertyDecorator {
    return (target: any, key: string, propDesc?: PropertyDescriptor) => {
        const privateKey = '_' + key.toString();
        propDesc = propDesc || {
            configurable: true,
            enumerable: true,
        };
        propDesc.get = propDesc.get || (function (this: any) {
            return this[privateKey];
        });
        const originalSetter = propDesc.set || (function (this: any, val: any) {
            this[privateKey] = val;
        });

        propDesc.set = function (this: any, val: any) {
            const init = this._init;
            const oldValue = this[key];
            if (val !== oldValue || (typeof val === 'object' && val === oldValue)) {
                originalSetter.call(this, val);
                if (this.ngOnChanges && !init) {
                    // in case wacthed prop changes trigger ngOnChanges manually
                    const changes: SimpleChanges = {
                        [key]: new SimpleChange(oldValue, val, false)
                    };
                    this.ngOnChanges(changes);
                }
            }
        };
        return propDesc;
    };
}

export function WatchColumnChanges(): PropertyDecorator {
    return (target: any, key: string, propDesc?: PropertyDescriptor) => {
        const privateKey = '_' + key.toString();
        propDesc = propDesc || {
            configurable: true,
            enumerable: true,
        };
        propDesc.get = propDesc.get || (function (this: any) {
            return this[privateKey];
        });
        const originalSetter = propDesc.set || (function (this: any, val: any) {
            this[privateKey] = val;
        });

        propDesc.set = function (this: any, val: any) {
            const oldValue = this[key];
            originalSetter.call(this, val);
            if (val !== oldValue || (typeof val === 'object' && val === oldValue)) {
                if (this.columnChange) {
                    this.columnChange.emit();
                }
            }
        };
        return propDesc;
    };
}

export function notifyChanges(repaint = false) {
    return (_: any, key: string, propDesc?: PropertyDescriptor) => {

        const privateKey = `__${key}`;

        propDesc = propDesc || {
            enumerable: true,
            configurable: true
        };


        const originalSetter = propDesc ? propDesc.set : null;
        propDesc.get = propDesc.get || (function (this) {
            return this[privateKey];
        });

        propDesc.set = function (this, newValue) {
            if (originalSetter) {
                originalSetter.call(this, newValue);
                if (this.grid) {
                    this.grid.notifyChanges(repaint && !this.grid.isPivot);
                }
            } else {
                if (newValue === this[key]) {
                    return;
                }
                this[privateKey] = newValue;
                if (this.grid) {
                    this.grid.notifyChanges(repaint && !this.grid.isPivot);
                }
            }
        };
        return propDesc as any;
    };
}