不使用正则表达式 Javascript 删除两个字符之间的字符串

Question

I'm trying to remove a sentence from a text file that I'm uploading through an Input file. I need to remove all sentences that are between '/ ' and ' /' so comments line basically. Also all the single line comments such as '//' but I took care of it already. For that I'm not allowed to use any regex or replace function. Is there anyone who can help me on that ? Thanks

class Inpute extends Component{
  constructor(props){
    super(props);
    this.state = {
      fileName: '',
      fileContent: ''
    };
  }

  handleFile = e =>{
    const file = e.target.files[0];
    const reader = new FileReader();
    reader.readAsText(file);
    reader.onload = () => {
      this.setState({fileName: file.name, fileContent: reader.result});
      if(reader.result.includes('//')){
        var newText = reader.result
        newText = newText
                .split('\n')
                .filter(x => !x.includes('\/\/'))
                .join('\n')

        this.setState({fileName: file.name, fileContent: newText})
      }
    }
    reader.onerror = () =>{
      console.log('File Error : ', reader.error)
    }
  }

Answer 1

Split string by / . Parts that you need to delete are all in odd indexes so filter them out and join this array back into string.

 const string = 'asdasada a/kkkkkkkk/a sdad asda s/xxxxx/s dasd'; const arr = string.split('/').filter((_, index) => index%2 === 0); console.log(arr.join(''));

UPDATE

I have changed my example to filter only comments

 const line = 'asdasada a/*kkkkkkkk*/a sdad asda s/*xxxxxs dasd x asda sd\\n' + 'asdas */das a// asdasda\\n' + 'x/*bbbbb*/c ad'; let prevPart = null; let haveDoubleSlashes = false; const cleaned = line.split('/').map(part => { // single line comments if (haveDoubleSlashes || part === '') { haveDoubleSlashes = true; if (part.includes('\\n')) { part = '\\n' + part.split('\\n')[1]; haveDoubleSlashes = false; } else { part = null; } return part; } /* multiline comments */ if (part.startsWith('*') && part.endsWith('*')) { prevPart = null; return null; } if (prevPart !== null) { part = '/' + part; } prevPart = part; return part; }).filter(part => part !== null).join(''); console.log(cleaned);

Answer 2

If all you care about is if the line contains two solidus characters ( / ), just filter on that:

 const sample = `blah blah // blah blah\\nblah blah /blah blah/ blah\\nblah blah blah`; const lines = sample.split('\\n'); const good = lines.filter(x => // [...x] makes the line an array of characters // reduce runs for each character, aggregating the result. // agg is the aggregation, cur is the current character // Here it's just counting the number of /s and returning false if there are // fewer than two [...x].reduce((agg, cur) => agg = cur === '/' ? agg + 1 : agg, 0) < 2 ); console.log(good.join('\\n'));

Answer 3

 function stripMultilineComments(str) { let posOpen; let posClose; while ((posOpen = str.indexOf('/*')) !== -1) { posClose = Math.max( 0, str.indexOf('*/', (posOpen + 2)) ) || (str.length - 2); str = [ str.substring(0, posOpen), str.substring(posClose + 2), ].join(''); } return str; } function stripSingleLineComment(str) { let idx; if ( (str.trim() !== '') && ((idx = str.indexOf('//')) !== -1) ) { str = str.substring(0, idx); } return str; } function stripComments(value) { return stripMultilineComments( String(value) ) .split('\\n') .map(stripSingleLineComment) .join('\\n'); } const sampleData = ` Lorem ipsum dolor sit amet/*, consectetur adipiscing elit, sed do eiusmod tempor incididunt*/ ut labore et dolore magna aliqua. // Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris/*nisi ut aliquip ex ea commodo consequat*/. Duis aute irure dolor in reprehenderit// in voluptate velit esse cillum dolore eu fugiat nulla pariatur.// Excepteur sint occaecat /*cupidatat non proident, */sunt in culpa qui officia deserunt mollit anim id est laborum. `; console.log( stripComments(sampleData) ); console.log( stripComments(sampleData) === ` Lorem ipsum dolor sit amet ut labore et dolore magna aliqua. quis nostrud exercitation ullamco laboris. Duis aute irure dolor in reprehenderit eu fugiat nulla pariatur. sunt in culpa qui officia deserunt mollit anim id est laborum. `);

 .as-console-wrapper { min-height: 100%!important; top: 0; }