当 LWC JS 中超过最大字符限制时，有没有办法在 Lightning 输入富文本字段中更改字体颜色？

Question

I'm trying to get the character count and on that basis want to change the color of font.

I have tried with queryselector() but it is not working:

handleChange(event) {
         if( this.charCount > 100){        
              let textcolor = this.template.queryselector("lightning-input-rich-text");
                 textcolor.getformat({color:"red"});
              }
        }
        

I have also tried with:

        handleChange(event) {
         if( this.charCount > 100){  
               textcolor = this.template.queryselector('[data-id="summary"]');
           if(textcolor) 
                    this.template.querySelector('[data- 
 id="summarytextcolor"]').className='summarytext';
                 
        }
        }

Here is my CSS:

.summarytext {color: #ff0000;}

And here is my lightning code, where I have taken a rich text field where on change I need to capture the number of character count:

<lightning-input-rich-text
         data-id="summary"
        label={label.Summary}
        formats={richTextformats}
        label-visible
         valid={richTextValidity}
         message-when-bad-input={richTextErrorMessage}
        class="slds-form-element slds-form-element_stacked summarytext"
        onchange={handleChange}
        value={richTextValue}
        style=" font-weight: normal;">
    </lightning-input-rich-text>

Here is the error I'm getting:

[NoErrorObjectAvailable] Script error.    a()@https://static.lightning.force.com/cs10/auraFW/javascript/7p9HLMpgnV2GO9MqZhXGUw/aura_prod.js:948:169 {anonymous}()@https://static.lightning.force.com/cs10/auraFW/javascript/7p9HLMpgnV2GO9MqZhXGUw/aura_prod.js:948:362 bt.dispatchEvent()@https://static.lightning.force.com/cs10/auraFW/javascript/7p9HLMpgnV2GO9MqZhXGUw/aura_prod.js:12:12146 bt.dispatchChangeEvent()@https://customization-velocity-2311-dev-ed.lightning.force.com/components/interop/inputRichText.js:2:28144 eval()@https://customization-velocity-2311-dev-ed.lightning.force.com/components/interop/inputRichText.js:2:20578 e.l.emit()@https://customization-velocity-2311-dev-ed.lightning.force.com/components/lightning/quillLib.js:2:142032 e.value()@https://customization-velocity-2311-dev-ed.lightning.force.com/components/lightning/quillLib.js:2:33139

What's the problem, and how can I fix it?

Answer 1

You should be able to set it using vanilla javascript.

handleChange(event) {
        this.loading = true;
        if(this.charCount > 100){        
             var warn = richTextValue.fontcolor("Red");
             this.richTextValue = warn;
        }
        this.loading = false;
}

I added a variable 'loading'; just make sure the input rich text is wrapped in a <template if:false={loading}> so the color of the font gets re-rendered.