feat(form-core): support format on paste

.changeset/wicked-games-dress.md

@@ -0,0 +1,5 @@
+---
+'@lion/form-core': minor
+---
+
+support paste functionality in FormatMixin

packages/form-core/src/FormatMixin.js

@@ -129,7 +129,7 @@ const FormatMixinImplementation = superclass =>
     }
 
     // We don't delegate, because we want to preserve caret position via _setValueAndPreserveCaret
-    /** @type {string} */
+    /** @param {string} value */
     set value(value) {
       // if not yet connected to dom can't change the value
       if (this._inputNode) {
@@ -350,7 +350,16 @@ const FormatMixinImplementation = superclass =>
       if (!this.__isHandlingComposition) {
         this.value = this.preprocessor(this.value);
       }
+      const prevFormatted = this.formattedValue;
       this.modelValue = this._callParser(this.value);
+
+      // Sometimes, the formattedValue didn't change, but the viewValue did...
+      // We need this check to support pasting values that need to be formatted right on paste
+      if (prevFormatted === this.formattedValue && this.__prevViewValue !== this.value) {
+        this._calculateValues();
+      }
+      /** @type {string} */
+      this.__prevViewValue = this.value;
     }
 
     /**
@@ -379,11 +388,13 @@ const FormatMixinImplementation = superclass =>
       return !this._isHandlingUserInput;
     }
 
-    // This can be called whenever the view value should be updated. Dependent on component type
-    // ("input" for <input> or "change" for <select>(mainly for IE)) a different event should be
-    // used  as source for the "user-input-changed" event (which can be seen as an abstraction
-    // layer on top of other events (input, change, whatever))
-    /** @protected */
+    /**
+     * This can be called whenever the view value should be updated. Dependent on component type
+     * ("input" for <input> or "change" for <select>(mainly for IE)) a different event should be
+     * used  as source for the "user-input-changed" event (which can be seen as an abstraction
+     * layer on top of other events (input, change, whatever))
+     * @protected
+     */
     _proxyInputEvent() {
       this.dispatchEvent(
         new CustomEvent('user-input-changed', {
@@ -419,8 +430,36 @@ const FormatMixinImplementation = superclass =>
       super();
       this.formatOn = 'change';
       this.formatOptions = /** @type {FormatOptions} */ ({});
-
+      /**
+       * Whether the user is pasting content. Allows Subclassers to do this in their subclass:
+       * @example
+       * ```js
+       * _reflectBackFormattedValueToUser() {
+       *   return super._reflectBackFormattedValueToUser() || this._isPasting;
+       * }
+       * ```
+       * @protected
+       */
+      this._isPasting = false;
+      /**
+       * @private
+       * @type {string}
+       */
+      this.__prevViewValue = '';
       this.__onCompositionEvent = this.__onCompositionEvent.bind(this);
+      // This computes formattedValue
+      this.addEventListener('user-input-changed', this._onUserInputChanged);
+      // This sets the formatted viewValue after paste
+      this.addEventListener('paste', this.__onPaste);
+    }
+
+    __onPaste() {
+      this._isPasting = true;
+      this.formatOptions.mode = 'pasted';
+      setTimeout(() => {
+        this._isPasting = false;
+        this.formatOptions.mode = 'auto';
+      });
     }
 
     connectedCallback() {
@@ -432,7 +471,7 @@ const FormatMixinImplementation = superclass =>
         // is guaranteed to be calculated
         setTimeout(this._reflectBackFormattedValueToUser);
       };
-      this.addEventListener('user-input-changed', this._onUserInputChanged);
+
       // Connect the value found in <input> to the formatting/parsing/serializing loop as a
       // fallback mechanism. Assume the user uses the value property of the
       // `LionField`(recommended api) as the api (this is a downwards sync).
@@ -453,7 +492,6 @@ const FormatMixinImplementation = superclass =>
 
     disconnectedCallback() {
       super.disconnectedCallback();
-      this.removeEventListener('user-input-changed', this._onUserInputChanged);
       if (this._inputNode) {
         this._inputNode.removeEventListener('input', this._proxyInputEvent);
         this._inputNode.removeEventListener(

packages/form-core/src/NativeTextFieldMixin.js

@@ -1,6 +1,7 @@
 import { dedupeMixin } from '@lion/core';
 import { FormControlMixin } from './FormControlMixin.js';
 import { FocusMixin } from './FocusMixin.js';
+import { FormatMixin } from './FormatMixin.js';
 
 /**
  * @typedef {import('../types/NativeTextFieldMixinTypes').NativeTextFieldMixin} NativeTextFieldMixin
@@ -8,7 +9,7 @@ import { FocusMixin } from './FocusMixin.js';
  * @param {import('@open-wc/dedupe-mixin').Constructor<import('@lion/core').LitElement>} superclass} superclass
  */
 const NativeTextFieldMixinImplementation = superclass =>
-  class NativeTextFieldMixin extends FocusMixin(FormControlMixin(superclass)) {
+  class NativeTextFieldMixin extends FormatMixin(FocusMixin(FormControlMixin(superclass))) {
     /**
      * @protected
      * @type {HTMLInputElement | HTMLTextAreaElement}
@@ -95,6 +96,20 @@ const NativeTextFieldMixinImplementation = superclass =>
         this._inputNode.value = newValue;
       }
     }
+
+    /**
+     * @override FormatMixin
+     */
+    _reflectBackFormattedValueToUser() {
+      super._reflectBackFormattedValueToUser();
+      if (this._reflectBackOn() && this.focused) {
+        try {
+          // try/catch, because Safari is a bit sensitive here
+          this._inputNode.selectionStart = this._inputNode.value.length;
+          // eslint-disable-next-line no-empty
+        } catch (_) {}
+      }
+    }
   };
 
 export const NativeTextFieldMixin = dedupeMixin(NativeTextFieldMixinImplementation);

packages/form-core/test-suites/FormatMixin.suite.js

@@ -462,6 +462,73 @@ export function runFormatMixinSuite(customConfig) {
           expect(spyArg.locale).to.equal('en-GB');
           expect(spyArg.decimalSeparator).to.equal('-');
         });
+
+        describe('On paste', () => {
+          class ReflectOnPaste extends FormatClass {
+            _reflectBackOn() {
+              return super._reflectBackOn() || this._isPasting;
+            }
+          }
+          const reflectingTagString = defineCE(ReflectOnPaste);
+          const reflectingTag = unsafeStatic(reflectingTagString);
+
+          /**
+           * @param {FormatClass} el
+           */
+          function paste(el, val = 'lorem') {
+            const { _inputNode } = getFormControlMembers(el);
+            _inputNode.value = val;
+            _inputNode.dispatchEvent(new ClipboardEvent('paste', { bubbles: true }));
+            _inputNode.dispatchEvent(new Event('input', { bubbles: true }));
+          }
+
+          it('sets formatOptions.mode to "pasted" (and restores to "auto")', async () => {
+            const el = /** @type {FormatClass} */ (await fixture(html`
+            <${reflectingTag}><input slot="input"></${reflectingTag}>
+          `));
+            const formatterSpy = sinon.spy(el, 'formatter');
+            paste(el);
+            expect(formatterSpy).to.be.called;
+            expect(/** @type {{mode: string}} */ (formatterSpy.args[0][1]).mode).to.equal('pasted');
+            await aTimeout(0);
+            mimicUserInput(el, '');
+            expect(/** @type {{mode: string}} */ (formatterSpy.args[0][1]).mode).to.equal('auto');
+          });
+
+          it('sets protected value "_isPasting" for Subclassers', async () => {
+            const el = /** @type {FormatClass} */ (await fixture(html`
+            <${reflectingTag}><input slot="input"></${reflectingTag}>
+          `));
+            const formatterSpy = sinon.spy(el, 'formatter');
+            paste(el);
+            expect(formatterSpy).to.have.been.called;
+            // @ts-ignore [allow-protected] in test
+            expect(el._isPasting).to.be.true;
+            await aTimeout(0);
+            // @ts-ignore [allow-protected] in test
+            expect(el._isPasting).to.be.false;
+          });
+
+          it('calls formatter and "_reflectBackOn()"', async () => {
+            const el = /** @type {FormatClass} */ (await fixture(html`
+            <${tag}><input slot="input"></${tag}>
+          `));
+            // @ts-ignore [allow-protected] in test
+            const reflectBackSpy = sinon.spy(el, '_reflectBackOn');
+            paste(el);
+            expect(reflectBackSpy).to.have.been.called;
+          });
+
+          it(`updates viewValue when "_reflectBackOn()" configured to reflect`, async () => {
+            const el = /** @type {FormatClass} */ (await fixture(html`
+            <${reflectingTag}><input slot="input"></${reflectingTag}>
+          `));
+            // @ts-ignore [allow-protected] in test
+            const reflectBackSpy = sinon.spy(el, '_reflectBackOn');
+            paste(el);
+            expect(reflectBackSpy).to.have.been.called;
+          });
+        });
       });
 
       describe('Parser', () => {

packages/form-core/types/FormatMixinTypes.d.ts

@@ -1,5 +1,5 @@
 import { Constructor } from '@open-wc/dedupe-mixin';
-import { LitElement } from '@lion/core';
+import { BooleanAttributePart, LitElement } from '@lion/core';
 import { FormatNumberOptions } from '@lion/localize/types/LocalizeMixinTypes';
 import { ValidateHost } from './validate/ValidateMixinTypes';
 import { FormControlHost } from './FormControlMixinTypes';
@@ -18,6 +18,16 @@ export declare class FormatHost {
   set value(value: string);
 
   protected _isHandlingUserInput: boolean;
+  /**
+   * Whether the user is pasting content. Allows Subclassers to do this in their subclass:
+   * @example
+   * ```js
+   * _reflectBackFormattedValueToUser() {
+   *   return super._reflectBackFormattedValueToUser() || this._isPasting;
+   * }
+   * ```
+   */
+  protected _isPasting: boolean;
   protected _calculateValues(opts: { source: 'model' | 'serialized' | 'formatted' | null }): void;
   protected _onModelValueChanged(arg: { modelValue: unknown }): void;
   protected _dispatchModelValueChangedEvent(): void;
@@ -31,6 +41,7 @@ export declare class FormatHost {
   protected _callFormatter(): string;
 
   private __preventRecursiveTrigger: boolean;
+  private __prevViewValue: string;
 }
 
 export declare function FormatImplementation<T extends Constructor<LitElement>>(

packages/form-core/types/NativeTextFieldMixinTypes.d.ts

@@ -2,6 +2,7 @@ import { Constructor } from '@open-wc/dedupe-mixin';
 import { LitElement } from '@lion/core';
 import { FocusHost } from '@lion/form-core/types/FocusMixinTypes';
 import { FormControlHost } from '@lion/form-core/types/FormControlMixinTypes';
+import { FormatHost } from '@lion/form-core/types/FormatMixinTypes';
 
 export declare class NativeTextFieldHost {
   get selectionStart(): number;
@@ -15,6 +16,8 @@ export declare function NativeTextFieldImplementation<T extends Constructor<LitE
 ): T &
   Constructor<NativeTextFieldHost> &
   Pick<typeof NativeTextFieldHost, keyof typeof NativeTextFieldHost> &
+  Constructor<FormatHost> &
+  Pick<typeof FormatHost, keyof typeof FormatHost> &
   Constructor<FocusHost> &
   Pick<typeof FocusHost, keyof typeof FocusHost> &
   Constructor<FormControlHost> &