coerce-property

Utility decorator functions for coercing Angular component @Inputs into specific types.

Used by Angular CDK coercions.

Support

Support Angular >=15.

Installation

# Do not forget to check if Angular CDK is installed
npm i -S @angular/cdk

# And install this package
npm i -S coerce-property

Coercions

• @coerce - decorator factory

  • @coerceBoolean- coerces a data-bound value (typically a string) to a boolean

    For example:

    <app-component disabled></app-component>

    @Input()
    @coerceBoolean
    disabled: boolean; // true

  • @coerceArray- wraps the provided value in an array, unless the provided value is an array

    For example:

    <app-component items="item"></app-component>

    @Input()
    @coerceArray
    items: string[]; // ['item']

  • @coercePixel - coerces a value to a CSS pixel value

    For example:

    <app-component [width]="200"></app-component>

    @Input()
    @coercePixel
    width: string; // '200px'

  • @coerceElement - coerces an ElementRef or an Element into an element

  • @coerceNumber - coerces a data-bound value (typically a string) to a number

    For example:

    <app-component age="19"></app-component>

    @Input()
    @coerceNumber
    age: number; // 19

Usage

import { Component, Input } from "@angular/core";
import { coerceBoolean } from "coerce-property";

@Component({
  selector: "app-component",
  template: ``,
})
export class SampleComponent {
  @Input()
  @coerceBoolean
  disabled: boolean;
}

You can use:

<app-sample [disabled]="true"></app-sample>

and

<app-sample disabled></app-sample>

How does it work

import { Component, Input } from "@angular/core";
import { coerceBooleanProperty } from "@angular/cdk/coercion";

@Component({
  selector: "app-component",
  template: ``,
})
export class SampleComponent {
  private _dsiabled: boolean;
  @Input()
  get disabled() {
    return this._dsiabled;
  }
  set disabled(disabled) {
    this._disabled = coerceBooleanProperty(disabled);
  }
}

// @angular/cdk/coercion/boolean-property.ts

export function coerceBooleanProperty(value: any): boolean {
  return value != null && `${value}` !== "false";
}