FLinesOfDuplicatedCode.ql

/**
 * @name Duplicated lines in files
 * @description The number of lines in a file (including code, comment and whitespace lines)
 *              occurring in a block of lines that is duplicated at least once somewhere else.
 * @kind treemap
 * @treemap.warnOn highValues
 * @metricType file
 * @metricAggregate avg sum max
 * @precision high
 * @id js/duplicated-lines-in-files
 * @tags testability
 *       duplicate-code
 *       non-attributable
 */

import external.CodeDuplication

/**
 * Holds if line `l` of file `f` should be excluded from duplicated code detection.
 *
 * Currently, only lines on which an import declaration occurs are excluded.
 */
predicate whitelistedLineForDuplication(File f, int l) {
  exists(ImportDeclaration i | i.getFile() = f and i.getLocation().getStartLine() = l)
}

/**
 * Holds if line `l` of file `f` belongs to a block of lines that is duplicated somewhere else.
 */
predicate dupLine(int l, File f) {
  exists(DuplicateBlock d | d.sourceFile() = f |
    l in [d.sourceStartLine() .. d.sourceEndLine()] and
    not whitelistedLineForDuplication(f, l)
  )
}

from File f, int n
where n = count(int l | dupLine(l, f))
select f, n order by n desc