Use template strings.

Author: RubenVerborgh

.eslintrc

@@ -166,6 +166,7 @@
     padded-blocks: [2, "never"],
     prefer-arrow-callback: 2,
     prefer-const: 2,
+    prefer-template: 2,
     quote-props: [2, "consistent-as-needed"],
     quotes: [2, "single", "avoid-escape"],
     semi-spacing: 2,
@@ -178,6 +179,7 @@
     space-infix-ops: 2,
     space-unary-ops: 2,
     spaced-comment: [2, "always", { block: { markers: ["!"] } }],
+    template-curly-spacing: 2,
     wrap-regex: 0,
   },
 }

perf/N3Lexer-perf.js

@@ -10,7 +10,7 @@ if (process.argv.length !== 3) {
 
 const filename = process.argv[2];
 
-const TEST = '- Lexing file ' + filename;
+const TEST = `- Lexing file ${filename}`;
 console.time(TEST);
 
 let count = 0;
@@ -19,7 +19,7 @@ new N3.Lexer().tokenize(fs.createReadStream(filename), (error, token) => {
   count++;
   if (token.type === 'eof') {
     console.timeEnd(TEST);
-    console.log('* Tokens lexed: ' + count);
-    console.log('* Memory usage: ' + Math.round(process.memoryUsage().rss / 1024 / 1024) + 'MB');
+    console.log(`* Tokens lexed: ${count}`);
+    console.log(`* Memory usage: ${Math.round(process.memoryUsage().rss / 1024 / 1024)}MB`);
   }
 });

perf/N3Parser-perf.js

@@ -10,9 +10,9 @@ if (process.argv.length !== 3) {
 }
 
 const filename = path.resolve(process.cwd(), process.argv[2]),
-    base = 'file://' + filename;
+    base = `file://${filename}`;
 
-const TEST = '- Parsing file ' + filename;
+const TEST = `- Parsing file ${filename}`;
 console.time(TEST);
 
 let count = 0;
@@ -22,7 +22,7 @@ new N3.Parser({ baseIRI: base }).parse(fs.createReadStream(filename), (error, qu
     count++;
   else {
     console.timeEnd(TEST);
-    console.log('* Quads parsed: ' + count);
-    console.log('* Memory usage: ' + Math.round(process.memoryUsage().rss / 1024 / 1024) + 'MB');
+    console.log(`* Quads parsed: ${count}`);
+    console.log(`* Memory usage: ${Math.round(process.memoryUsage().rss / 1024 / 1024)}MB`);
   }
 });

perf/N3Store-perf.js

@@ -12,7 +12,7 @@ let dimSquared = dim * dim;
 let dimCubed = dimSquared * dim;
 
 let store = new N3.Store();
-let TEST = '- Adding ' + dimCubed + ' triples to the default graph';
+let TEST = `- Adding ${dimCubed} triples to the default graph`;
 console.time(TEST);
 let i, j, k, l;
 for (i = 0; i < dim; i++)
@@ -21,17 +21,17 @@ for (i = 0; i < dim; i++)
       store.addQuad(prefix + i, prefix + j, prefix + k);
 console.timeEnd(TEST);
 
-console.log('* Memory usage for triples: ' + Math.round(process.memoryUsage().rss / 1024 / 1024) + 'MB');
+console.log(`* Memory usage for triples: ${Math.round(process.memoryUsage().rss / 1024 / 1024)}MB`);
 
-TEST = '- Finding all ' + dimCubed + ' triples in the default graph ' + dimSquared * 1 + ' times (0 variables)';
+TEST = `- Finding all ${dimCubed} triples in the default graph ${dimSquared * 1} times (0 variables)`;
 console.time(TEST);
 for (i = 0; i < dim; i++)
   for (j = 0; j < dim; j++)
     for (k = 0; k < dim; k++)
       assert.equal(store.getQuads(prefix + i, prefix + j, prefix + k, '').length, 1);
 console.timeEnd(TEST);
 
-TEST = '- Finding all ' + dimCubed + ' triples in the default graph ' + dimSquared * 2 + ' times (1 variable)';
+TEST = `- Finding all ${dimCubed} triples in the default graph ${dimSquared * 2} times (1 variable)`;
 console.time(TEST);
 for (i = 0; i < dim; i++)
   for (j = 0; j < dim; j++)
@@ -44,7 +44,7 @@ for (i = 0; i < dim; i++)
     assert.equal(store.getQuads(null, prefix + i, prefix + j, '').length, dim);
 console.timeEnd(TEST);
 
-TEST = '- Finding all ' + dimCubed + ' triples in the default graph ' + dimSquared * 3 + ' times (2 variables)';
+TEST = `- Finding all ${dimCubed} triples in the default graph ${dimSquared * 3} times (2 variables)`;
 console.time(TEST);
 for (i = 0; i < dim; i++)
   assert.equal(store.getQuads(prefix + i, null, null, '').length, dimSquared);
@@ -63,7 +63,7 @@ dimCubed = dimSquared * dim;
 const dimQuads = dimCubed * dim;
 
 store = new N3.Store();
-TEST = '- Adding ' + dimQuads + ' quads';
+TEST = `- Adding ${dimQuads} quads`;
 console.time(TEST);
 for (i = 0; i < dim; i++)
   for (j = 0; j < dim; j++)
@@ -72,9 +72,9 @@ for (i = 0; i < dim; i++)
         store.addQuad(prefix + i, prefix + j, prefix + k, prefix + l);
 console.timeEnd(TEST);
 
-console.log('* Memory usage for quads: ' + Math.round(process.memoryUsage().rss / 1024 / 1024) + 'MB');
+console.log(`* Memory usage for quads: ${Math.round(process.memoryUsage().rss / 1024 / 1024)}MB`);
 
-TEST = '- Finding all ' + dimQuads + ' quads ' + dimCubed * 4 + ' times';
+TEST = `- Finding all ${dimQuads} quads ${dimCubed * 4} times`;
 console.time(TEST);
 for (i = 0; i < dim; i++)
   assert.equal(store.getQuads(prefix + i, null, null, null).length, dimCubed);

src/IRIs.js

@@ -4,27 +4,27 @@ const RDF  = 'http://www.w3.org/1999/02/22-rdf-syntax-ns#',
 
 export default {
   xsd: {
-    decimal: XSD + 'decimal',
-    boolean: XSD + 'boolean',
-    double:  XSD + 'double',
-    integer: XSD + 'integer',
-    string:  XSD + 'string',
+    decimal: `${XSD}decimal`,
+    boolean: `${XSD}boolean`,
+    double:  `${XSD}double`,
+    integer: `${XSD}integer`,
+    string:  `${XSD}string`,
   },
   rdf: {
-    type:       RDF + 'type',
-    nil:        RDF + 'nil',
-    first:      RDF + 'first',
-    rest:       RDF + 'rest',
-    langString: RDF + 'langString',
+    type:       `${RDF}type`,
+    nil:        `${RDF}nil`,
+    first:      `${RDF}first`,
+    rest:       `${RDF}rest`,
+    langString: `${RDF}langString`,
   },
   owl: {
     sameAs: 'http://www.w3.org/2002/07/owl#sameAs',
   },
   r: {
-    forSome: SWAP + 'reify#forSome',
-    forAll:  SWAP + 'reify#forAll',
+    forSome: `${SWAP}reify#forSome`,
+    forAll:  `${SWAP}reify#forAll`,
   },
   log: {
-    implies: SWAP + 'log#implies',
+    implies: `${SWAP}log#implies`,
   },
 };

src/N3DataFactory.js

@@ -128,7 +128,7 @@ export class Literal extends Term {
 // ## BlankNode constructor
 export class BlankNode extends Term {
   constructor(name) {
-    super('_:' + name);
+    super(`_:${name}`);
   }
 
   // ### The term type of this term
@@ -144,7 +144,7 @@ export class BlankNode extends Term {
 
 export class Variable extends Term {
   constructor(name) {
-    super('?' + name);
+    super(`?${name}`);
   }
 
   // ### The term type of this term
@@ -234,12 +234,12 @@ export function termToId(term) {
   // Term instantiated with another library
   switch (term.termType) {
   case 'NamedNode':    return term.value;
-  case 'BlankNode':    return '_:' + term.value;
-  case 'Variable':     return '?' + term.value;
+  case 'BlankNode':    return `_:${term.value}`;
+  case 'Variable':     return `?${term.value}`;
   case 'DefaultGraph': return '';
-  case 'Literal':      return '"' + term.value + '"' +
-    (term.language ? '@' + term.language :
-      (term.datatype && term.datatype.value !== xsd.string ? '^^' + term.datatype.value : ''));
+  case 'Literal':      return `"${term.value}"${
+    term.language ? `@${term.language}` :
+      (term.datatype && term.datatype.value !== xsd.string ? `^^${term.datatype.value}` : '')}`;
   case 'Quad':
     // To identify RDF* quad components, we escape quotes by doubling them.
     // This avoids the overhead of backslash parsing of Turtle-like syntaxes.
@@ -252,7 +252,7 @@ export function termToId(term) {
       }${
         (isDefaultGraph(term.graph)) ? '' : ` ${termToId(term.graph)}`
       }>>`;
-  default: throw new Error('Unexpected termType: ' + term.termType);
+  default: throw new Error(`Unexpected termType: ${term.termType}`);
   }
 }
 
@@ -317,7 +317,7 @@ function blankNode(name) {
 function literal(value, languageOrDataType) {
   // Create a language-tagged string
   if (typeof languageOrDataType === 'string')
-    return new Literal('"' + value + '"@' + languageOrDataType.toLowerCase());
+    return new Literal(`"${value}"@${languageOrDataType.toLowerCase()}`);
 
   // Automatically determine datatype for booleans and numbers
   let datatype = languageOrDataType ? languageOrDataType.value : '';
@@ -339,8 +339,8 @@ function literal(value, languageOrDataType) {
 
   // Create a datatyped literal
   return (datatype === '' || datatype === xsd.string) ?
-    new Literal('"' + value + '"') :
-    new Literal('"' + value + '"^^' + datatype);
+    new Literal(`"${value}"`) :
+    new Literal(`"${value}"^^${datatype}`);
 }
 
 // ### Creates a variable

src/N3Lexer.js

@@ -163,7 +163,7 @@ export default class N3Lexer {
         // we always need a non-dot character before deciding it is a blank node.
         // Therefore, try inserting a space if we're at the end of the input.
         if ((match = this._blank.exec(input)) ||
-            inputFinished && (match = this._blank.exec(input + ' ')))
+            inputFinished && (match = this._blank.exec(`${input} `)))
           type = 'blank', prefix = '_', value = match[1];
         break;
 
@@ -241,7 +241,7 @@ export default class N3Lexer {
         // we always need a non-dot character before deciding it is a number.
         // Therefore, try inserting a space if we're at the end of the input.
         if (match = this._number.exec(input) ||
-            inputFinished && (match = this._number.exec(input + ' '))) {
+            inputFinished && (match = this._number.exec(`${input} `))) {
           type = 'literal', value = match[0];
           prefix = (typeof match[1] === 'string' ? xsd.double :
                     (typeof match[2] === 'string' ? xsd.decimal : xsd.integer));
@@ -320,7 +320,7 @@ export default class N3Lexer {
         // we always need a non-dot character before deciding it is a prefixed name.
         // Therefore, try inserting a space if we're at the end of the input.
         else if ((match = this._prefixed.exec(input)) ||
-                 inputFinished && (match = this._prefixed.exec(input + ' ')))
+                 inputFinished && (match = this._prefixed.exec(`${input} `)))
           type = 'prefixed', prefix = match[1] || '', value = this._unescape(match[2]);
       }
 
@@ -420,7 +420,7 @@ export default class N3Lexer {
   // ### `_syntaxError` creates a syntax error for the given issue
   _syntaxError(issue) {
     this._input = null;
-    const err = new Error('Unexpected "' + issue + '" on line ' + this._line + '.');
+    const err = new Error(`Unexpected "${issue}" on line ${this._line}.`);
     err.context = {
       token: undefined,
       line: this._line,

src/N3Parser.js

@@ -86,7 +86,7 @@ export default class N3Parser {
       this._inversePredicate = false;
       // In N3, blank nodes are scoped to a formula
       // (using a dot as separator, as a blank node label cannot start with it)
-      this._prefixes._ = (this._graph ? this._graph.id.substr(2) + '.' : '.');
+      this._prefixes._ = (this._graph ? `${this._graph.id.substr(2)}.` : '.');
       // Quantifiers are scoped to a formula
       this._quantified = Object.create(this._quantified);
     }
@@ -160,7 +160,7 @@ export default class N3Parser {
     case 'prefixed':
       const prefix = this._prefixes[token.prefix];
       if (prefix === undefined)
-        return this._error('Undefined prefix "' + token.prefix + ':"', token);
+        return this._error(`Undefined prefix "${token.prefix}:"`, token);
       value = this._namedNode(prefix + token.value);
       break;
     // Read a blank node
@@ -173,7 +173,7 @@ export default class N3Parser {
       break;
     // Everything else is not an entity
     default:
-      return this._error('Expected entity but got ' + token.type, token);
+      return this._error(`Expected entity but got ${token.type}`, token);
     }
     // In N3 mode, replace the entity if it is quantified
     if (!quantifier && this._n3Mode && (value.id in this._quantified))
@@ -265,7 +265,7 @@ export default class N3Parser {
     case '}':
       // Expected predicate didn't come, must have been trailing semicolon
       if (this._predicate === null)
-        return this._error('Unexpected ' + type, token);
+        return this._error(`Unexpected ${type}`, token);
       this._subject = null;
       return type === ']' ? this._readBlankNodeTail(token) : this._readPunctuation(token);
     case ';':
@@ -338,7 +338,7 @@ export default class N3Parser {
   // ### `_readGraph` reads a graph
   _readGraph(token) {
     if (token.type !== '{')
-      return this._error('Expected graph but got ' + token.type, token);
+      return this._error(`Expected graph but got ${token.type}`, token);
     // The "subject" we read is actually the GRAPH's label
     this._graph = this._subject, this._subject = null;
     return this._readSubject;
@@ -604,7 +604,7 @@ export default class N3Parser {
         next = this._readQuadPunctuation;
         break;
       }
-      return this._error('Expected punctuation to follow "' + this._object.id + '"', token);
+      return this._error(`Expected punctuation to follow "${this._object.id}"`, token);
     }
     // A quad has been completed now, so return it
     if (subject !== null) {
@@ -630,7 +630,7 @@ export default class N3Parser {
       next = this._readObject;
       break;
     default:
-      return this._error('Expected punctuation to follow "' + this._object.id + '"', token);
+      return this._error(`Expected punctuation to follow "${this._object.id}"`, token);
     }
     // A quad has been completed now, so return it
     this._emit(this._subject, this._predicate, this._object, this._graph);
@@ -655,7 +655,7 @@ export default class N3Parser {
   // ### `_readPrefixIRI` reads the IRI of a prefix declaration
   _readPrefixIRI(token) {
     if (token.type !== 'IRI')
-      return this._error('Expected IRI to follow prefix "' + this._prefix + ':"', token);
+      return this._error(`Expected IRI to follow prefix "${this._prefix}:"`, token);
     const prefixNode = this._readEntity(token);
     this._prefixes[this._prefix] = prefixNode.value;
     this._prefixCallback(this._prefix, prefixNode);
@@ -715,7 +715,7 @@ export default class N3Parser {
       if ((entity = this._readEntity(token, true)) !== undefined)
         break;
     default:
-      return this._error('Unexpected ' + token.type, token);
+      return this._error(`Unexpected ${token.type}`, token);
     }
     // Without explicit quantifiers, map entities to a quantified entity
     if (!this._explicitQuantifiers)
@@ -825,7 +825,7 @@ export default class N3Parser {
       // An entity means this is a quad (only allowed if not already inside a graph)
       if (this._supportsQuads && this._graph === null && (this._graph = this._readEntity(token)) !== undefined)
         return this._readRDFStarTail;
-      return this._error('Expected >> to follow "' + this._object.id + '"', token);
+      return this._error(`Expected >> to follow "${this._object.id}"`, token);
     }
     return this._readRDFStarTail(token);
   }
@@ -875,7 +875,7 @@ export default class N3Parser {
 
   // ### `_error` emits an error message through the callback
   _error(message, token) {
-    const err = new Error(message + ' on line ' + token.line + '.');
+    const err = new Error(`${message} on line ${token.line}.`);
     err.context = {
       token: token,
       line: token.line,
@@ -965,7 +965,7 @@ export default class N3Parser {
                 result = result.substr(0, segmentStart);
               // Remove a trailing '/..' segment
               if (next !== '/')
-                return result + '/' + iri.substr(i + 1);
+                return `${result}/${iri.substr(i + 1)}`;
               segmentStart = i + 1;
             }
           }
@@ -986,7 +986,7 @@ export default class N3Parser {
     this._sparqlStyle = false;
     this._prefixes = Object.create(null);
     this._prefixes._ = this._blankNodePrefix ? this._blankNodePrefix.substr(2)
-                                             : 'b' + blankNodePrefix++ + '_';
+                                             : `b${blankNodePrefix++}_`;
     this._prefixCallback = prefixCallback || noop;
     this._inversePredicate = false;
     this._quantified = Object.create(null);

src/N3Store.js

@@ -678,13 +678,13 @@ export default class N3Store {
     let name, index;
     // Generate a name based on the suggested name
     if (suggestedName) {
-      name = suggestedName = '_:' + suggestedName, index = 1;
+      name = suggestedName = `_:${suggestedName}`, index = 1;
       while (this._ids[name])
         name = suggestedName + index++;
     }
     // Generate a generic blank node name
     else {
-      do { name = '_:b' + this._blankNodeIndex++; }
+      do { name = `_:b${this._blankNodeIndex++}`; }
       while (this._ids[name]);
     }
     // Add the blank node to the entities, avoiding the generation of duplicates