Support for negative values

cypress/integration/clipboard-events.spec.ts

@@ -135,7 +135,7 @@ describe('Copy & Paste', () => {
     cy.get('#digit-only-decimal').clear();
   });
 
-  it.only('s', ()=> {
+  it('s', ()=> {
     const dt = new DataTransfer();
     dt.setData('text/plain', 'abc1.0s.1');
     const pasteEvent = new ClipboardEvent('paste', {
@@ -264,4 +264,28 @@ describe('Copy & Paste', () => {
 
     cy.get('#decimal-number').clear();
   });
+
+  it('should accept negative sign (only once)', () => {
+    const dt = new DataTransfer();
+    dt.setData('text/plain', '-123');
+    const pasteEvent = new ClipboardEvent('paste', {
+      clipboardData: dt,
+      bubbles: true,
+      cancelable: true,
+    });
+
+    cy.get('#negative-digit-only').clear();
+
+    cy.get('#negative-digit-only').then(($el) => {
+      $el[0].dispatchEvent(pasteEvent);
+      cy.get('#negative-digit-only').should('have.value', '-123');
+    });
+
+    cy.get('#negative-digit-only').then(($el) => {
+      $el[0].dispatchEvent(pasteEvent);
+      cy.get('#negative-digit-only').should('have.value', '-123123');
+    });
+
+    cy.get('#negative-digit-only').clear();
+  });
 });

projects/uiowa/digit-only/src/lib/digit-only.directive.ts

@@ -12,6 +12,7 @@ import {
 })
 export class DigitOnlyDirective implements OnChanges {
   private hasDecimalPoint = false;
+  private hasNegativeSign = false;
   private navigationKeys = [
     'Backspace',
     'Delete',
@@ -29,6 +30,8 @@ export class DigitOnlyDirective implements OnChanges {
 
   @Input() decimal = false;
   @Input() decimalSeparator = '.';
+  @Input() allowNegatives= false;
+  @Input() negativeSign = '-';
   @Input() min = -Infinity;
   @Input() max = Infinity;
   @Input() pattern?: string | RegExp;
@@ -58,7 +61,8 @@ export class DigitOnlyDirective implements OnChanges {
   @HostListener('beforeinput', ['$event'])
   onBeforeInput(e: InputEvent): any {
     if (isNaN(Number(e.data))) {
-      if (e.data === this.decimalSeparator) {
+      if (e.data === this.decimalSeparator
+          || (e.data === this.negativeSign && this.allowNegatives)) {
         return; // go on
       }
       e.preventDefault();
@@ -97,6 +101,17 @@ export class DigitOnlyDirective implements OnChanges {
       }
     }
 
+    if (e.key === this.negativeSign && this.allowNegatives) {
+      newValue = this.forecastValue(e.key);
+      if (newValue.charAt(0) !== this.negativeSign || newValue.split(this.negativeSign).length > 2) {
+        e.preventDefault();
+        return;
+      } else {
+        this.hasNegativeSign = newValue.split(this.negativeSign).length > -1;
+        return;
+      }
+    }
+
     // Ensure that it is a number and stop the keypress
     if (e.key === ' ' || isNaN(Number(e.key))) {
       e.preventDefault();
@@ -145,6 +160,11 @@ export class DigitOnlyDirective implements OnChanges {
 
   private pasteData(pastedContent: string): void {
     const sanitizedContent = this.sanitizeInput(pastedContent);
+    if (sanitizedContent.includes(this.negativeSign)
+        && this.hasNegativeSign
+        && !this.getSelection().includes(this.negativeSign)) {
+      return;
+    }
     const pasted = document.execCommand('insertText', false, sanitizedContent);
     if (!pasted) {
       if (this.inputElement.setRangeText) {
@@ -174,6 +194,7 @@ export class DigitOnlyDirective implements OnChanges {
       this.hasDecimalPoint =
         this.inputElement.value.indexOf(this.decimalSeparator) > -1;
     }
+    this.hasNegativeSign = this.inputElement.value.indexOf(this.negativeSign) > -1;
   }
 
   // The following 2 methods were added from the below article for browsers that do not support setRangeText
@@ -206,22 +227,27 @@ export class DigitOnlyDirective implements OnChanges {
 
   private sanitizeInput(input: string): string {
     let result = '';
+    let regex;
     if (this.decimal && this.isValidDecimal(input)) {
-      const regex = new RegExp(`[^0-9${this.decimalSeparator}]`, 'g');
-      result = input.replace(regex, '');
+      regex = new RegExp(`${this.getNegativeSignRegExp()}[^0-9${this.decimalSeparator}]`, 'g');
     } else {
-      result = input.replace(/[^0-9]/g, '');
+      regex = new RegExp(`${this.getNegativeSignRegExp()}[^0-9]`, 'g');
     }
+    result = input.replace(regex, '');
 
     const maxLength = this.inputElement.maxLength;
     if (maxLength > 0) {
       // the input element has maxLength limit
-      const allowedLength = maxLength - this.inputElement.value.length;
+      const allowedLength = maxLength - this.inputElement.value.length + (result.includes(`${this.negativeSign}`) ? 1 : 0);
       result = allowedLength > 0 ? result.substring(0, allowedLength) : '';
     }
     return result;
   }
 
+  private getNegativeSignRegExp() : string {
+    return this.allowNegatives && (!this.hasNegativeSign || this.getSelection().includes(this.negativeSign)) ? `(?!^${this.negativeSign})` : '';
+  }
+
   private isValidDecimal(string: string): boolean {
     if (!this.hasDecimalPoint) {
       return string.split(this.decimalSeparator).length <= 2;
@@ -247,11 +273,8 @@ export class DigitOnlyDirective implements OnChanges {
     const selectionStart = this.inputElement.selectionStart ?? 0;
     const selectionEnd = this.inputElement.selectionEnd ?? 0;
     const oldValue = this.inputElement.value;
-    const selection = oldValue.substring(selectionStart, selectionEnd);
-    return selection
-      ? oldValue.replace(selection, key)
-      : oldValue.substring(0, selectionStart) +
-          key +
-          oldValue.substring(selectionStart);
+    return oldValue.substring(0, selectionStart) +
+        key +
+        oldValue.substring(selectionEnd);
   }
 }

src/app/digit-only-demos/digit-only-demos.component.html

@@ -16,6 +16,9 @@ <h3><code>digitOnly</code> directive</h3>
       placeholder="000"
       maxlength="3"
     />
+
+    <label for="negative-digit-only">Digit Only input box that can be negative</label>
+    <input id="negative-digit-only" type="text" digitOnly [allowNegatives]="true" placeholder="-123"/>
   </section>
 
   <section>