From a24466089b6decf2f4118e06e78f038c137ad1f6 Mon Sep 17 00:00:00 2001 From: Project Nayuki Date: Thu, 1 Nov 2018 17:52:48 +0000 Subject: [PATCH] Tweaked TypeScript code to change 'let' declarations to 'const' wherever possible; but avoiding variables where objects are internally mutated (i.e. strict C++/Rust-style constness). --- typescript/qrcodegen.ts | 86 ++++++++++++++++++++--------------------- 1 file changed, 43 insertions(+), 43 deletions(-) diff --git a/typescript/qrcodegen.ts b/typescript/qrcodegen.ts index 9c3d4ff..2bb3e71 100644 --- a/typescript/qrcodegen.ts +++ b/typescript/qrcodegen.ts @@ -59,7 +59,7 @@ namespace qrcodegen { // QR Code version is automatically chosen for the output. The ECC level of the result may be higher than the // ecl argument if it can be done without increasing the version. public static encodeText(text: string, ecl: QrCode.Ecc): QrCode { - let segs: Array = qrcodegen.QrSegment.makeSegments(text); + const segs: Array = qrcodegen.QrSegment.makeSegments(text); return QrCode.encodeSegments(segs, ecl); } @@ -69,7 +69,7 @@ namespace qrcodegen { // bytes allowed is 2953. The smallest possible QR Code version is automatically chosen for the output. // The ECC level of the result may be higher than the ecl argument if it can be done without increasing the version. public static encodeBinary(data: Array, ecl: QrCode.Ecc): QrCode { - let seg: QrSegment = qrcodegen.QrSegment.makeBytes(data); + const seg: QrSegment = qrcodegen.QrSegment.makeBytes(data); return QrCode.encodeSegments([seg], ecl); } @@ -97,8 +97,8 @@ namespace qrcodegen { let version: int; let dataUsedBits: int; for (version = minVersion; ; version++) { - let dataCapacityBits: int = QrCode.getNumDataCodewords(version, ecl) * 8; // Number of data bits available - let usedBits: number = QrSegment.getTotalBits(segs, version); + const dataCapacityBits: int = QrCode.getNumDataCodewords(version, ecl) * 8; // Number of data bits available + const usedBits: number = QrSegment.getTotalBits(segs, version); if (usedBits <= dataCapacityBits) { dataUsedBits = usedBits; break; // This version number is found to be suitable @@ -108,24 +108,24 @@ namespace qrcodegen { } // Increase the error correction level while the data still fits in the current version number - for (let newEcl of [QrCode.Ecc.MEDIUM, QrCode.Ecc.QUARTILE, QrCode.Ecc.HIGH]) { // From low to high + for (const newEcl of [QrCode.Ecc.MEDIUM, QrCode.Ecc.QUARTILE, QrCode.Ecc.HIGH]) { // From low to high if (boostEcl && dataUsedBits <= QrCode.getNumDataCodewords(version, newEcl) * 8) ecl = newEcl; } // Concatenate all segments to create the data bit string let bb = new BitBuffer(); - for (let seg of segs) { + for (const seg of segs) { bb.appendBits(seg.mode.modeBits, 4); bb.appendBits(seg.numChars, seg.mode.numCharCountBits(version)); - for (let b of seg.getData()) + for (const b of seg.getData()) bb.push(b); } if (bb.length != dataUsedBits) throw "Assertion error"; // Add terminator and pad up to a byte if applicable - let dataCapacityBits: int = QrCode.getNumDataCodewords(version, ecl) * 8; + const dataCapacityBits: int = QrCode.getNumDataCodewords(version, ecl) * 8; if (bb.length > dataCapacityBits) throw "Assertion error"; bb.appendBits(0, Math.min(4, dataCapacityBits - bb.length)); @@ -202,7 +202,7 @@ namespace qrcodegen { // Compute ECC, draw modules this.drawFunctionPatterns(); - let allCodewords: Array = this.addEccAndInterleave(dataCodewords); + const allCodewords: Array = this.addEccAndInterleave(dataCodewords); this.drawCodewords(allCodewords); // Do masking @@ -211,7 +211,7 @@ namespace qrcodegen { for (let i = 0; i < 8; i++) { this.drawFormatBits(i); this.applyMask(i); - let penalty: int = this.getPenaltyScore(); + const penalty: int = this.getPenaltyScore(); if (penalty < minPenalty) { mask = i; minPenalty = penalty; @@ -248,7 +248,7 @@ namespace qrcodegen { public drawCanvas(scale: int, border: int, canvas: HTMLCanvasElement): void { if (scale <= 0 || border < 0) throw "Value out of range"; - let width: int = (this.size + border * 2) * scale; + const width: int = (this.size + border * 2) * scale; canvas.width = width; canvas.height = width; let ctx = canvas.getContext("2d") as CanvasRenderingContext2D; @@ -299,8 +299,8 @@ namespace qrcodegen { this.drawFinderPattern(3, this.size - 4); // Draw numerous alignment patterns - let alignPatPos: Array = this.getAlignmentPatternPositions(); - let numAlign: int = alignPatPos.length; + const alignPatPos: Array = this.getAlignmentPatternPositions(); + const numAlign: int = alignPatPos.length; for (let i = 0; i < numAlign; i++) { for (let j = 0; j < numAlign; j++) { // Don't draw on the three finder corners @@ -361,9 +361,9 @@ namespace qrcodegen { // Draw two copies for (let i = 0; i < 18; i++) { - let bt: boolean = getBit(bits, i); - let a: int = this.size - 11 + i % 3; - let b: int = Math.floor(i / 3); + const bt: boolean = getBit(bits, i); + const a: int = this.size - 11 + i % 3; + const b: int = Math.floor(i / 3); this.setFunctionModule(a, b, bt); this.setFunctionModule(b, a, bt); } @@ -375,9 +375,9 @@ namespace qrcodegen { private drawFinderPattern(x: int, y: int): void { for (let dy = -4; dy <= 4; dy++) { for (let dx = -4; dx <= 4; dx++) { - let dist: int = Math.max(Math.abs(dx), Math.abs(dy)); // Chebyshev/infinity norm - let xx: int = x + dx; - let yy: int = y + dy; + const dist: int = Math.max(Math.abs(dx), Math.abs(dy)); // Chebyshev/infinity norm + const xx: int = x + dx; + const yy: int = y + dy; if (0 <= xx && xx < this.size && 0 <= yy && yy < this.size) this.setFunctionModule(xx, yy, dist != 2 && dist != 4); } @@ -414,19 +414,19 @@ namespace qrcodegen { throw "Invalid argument"; // Calculate parameter numbers - let numBlocks: int = QrCode.NUM_ERROR_CORRECTION_BLOCKS[ecl.ordinal][ver]; - let blockEccLen: int = QrCode.ECC_CODEWORDS_PER_BLOCK [ecl.ordinal][ver]; - let rawCodewords: int = Math.floor(QrCode.getNumRawDataModules(ver) / 8); - let numShortBlocks: int = numBlocks - rawCodewords % numBlocks; - let shortBlockLen: int = Math.floor(rawCodewords / numBlocks); + const numBlocks: int = QrCode.NUM_ERROR_CORRECTION_BLOCKS[ecl.ordinal][ver]; + const blockEccLen: int = QrCode.ECC_CODEWORDS_PER_BLOCK [ecl.ordinal][ver]; + const rawCodewords: int = Math.floor(QrCode.getNumRawDataModules(ver) / 8); + const numShortBlocks: int = numBlocks - rawCodewords % numBlocks; + const shortBlockLen: int = Math.floor(rawCodewords / numBlocks); // Split data into blocks and append ECC to each block let blocks: Array> = []; - let rs = new ReedSolomonGenerator(blockEccLen); + const rs = new ReedSolomonGenerator(blockEccLen); for (let i = 0, k = 0; i < numBlocks; i++) { let dat: Array = data.slice(k, k + shortBlockLen - blockEccLen + (i < numShortBlocks ? 0 : 1)); k += dat.length; - let ecc: Array = rs.getRemainder(dat); + const ecc: Array = rs.getRemainder(dat); if (i < numShortBlocks) dat.push(0); blocks.push(dat.concat(ecc)); @@ -459,9 +459,9 @@ namespace qrcodegen { right = 5; for (let vert = 0; vert < this.size; vert++) { // Vertical counter for (let j = 0; j < 2; j++) { - let x: int = right - j; // Actual x coordinate - let upward: boolean = ((right + 1) & 2) == 0; - let y: int = upward ? this.size - 1 - vert : vert; // Actual y coordinate + const x: int = right - j; // Actual x coordinate + const upward: boolean = ((right + 1) & 2) == 0; + const y: int = upward ? this.size - 1 - vert : vert; // Actual y coordinate if (!this.isFunction[y][x] && i < data.length * 8) { this.modules[y][x] = getBit(data[i >>> 3], 7 - (i & 7)); i++; @@ -566,7 +566,7 @@ namespace qrcodegen { // 2*2 blocks of modules having same color for (let y = 0; y < this.size - 1; y++) { for (let x = 0; x < this.size - 1; x++) { - let color: boolean = this.modules[y][x]; + const color: boolean = this.modules[y][x]; if ( color == this.modules[y][x + 1] && color == this.modules[y + 1][x] && color == this.modules[y + 1][x + 1]) @@ -576,15 +576,15 @@ namespace qrcodegen { // Balance of black and white modules let black: int = 0; - for (let row of this.modules) { - for (let color of row) { + for (const row of this.modules) { + for (const color of row) { if (color) black++; } } - let total: int = this.size * this.size; // Note that size is odd, so black/total != 1/2 + const total: int = this.size * this.size; // Note that size is odd, so black/total != 1/2 // Compute the smallest integer k >= 0 such that (45-5k)% <= black/total <= (55+5k)% - let k: int = Math.ceil(Math.abs(black * 20 - total * 10) / total) - 1; + const k: int = Math.ceil(Math.abs(black * 20 - total * 10) / total) - 1; result += k * QrCode.PENALTY_N4; return result; } @@ -599,8 +599,8 @@ namespace qrcodegen { if (this.version == 1) return []; else { - let numAlign: int = Math.floor(this.version / 7) + 2; - let step: int = (this.version == 32) ? 26 : + const numAlign: int = Math.floor(this.version / 7) + 2; + const step: int = (this.version == 32) ? 26 : Math.ceil((this.size - 13) / (numAlign*2 - 2)) * 2; let result: Array = [6]; for (let pos = this.size - 7; result.length < numAlign; pos -= step) @@ -618,7 +618,7 @@ namespace qrcodegen { throw "Version number out of range"; let result: int = (16 * ver + 128) * ver + 64; if (ver >= 2) { - let numAlign: int = Math.floor(ver / 7) + 2; + const numAlign: int = Math.floor(ver / 7) + 2; result -= (25 * numAlign - 10) * numAlign - 55; if (ver >= 7) result -= 36; @@ -718,7 +718,7 @@ namespace qrcodegen { // can be converted to UTF-8 bytes and encoded as a byte mode segment. public static makeBytes(data: Array): QrSegment { let bb = new BitBuffer(); - for (let b of data) + for (const b of data) bb.appendBits(b, 8); return new QrSegment(QrSegment.Mode.BYTE, data.length, bb); } @@ -730,7 +730,7 @@ namespace qrcodegen { throw "String contains non-numeric characters"; let bb = new BitBuffer(); for (let i = 0; i < digits.length; ) { // Consume up to 3 digits per iteration - let n: int = Math.min(digits.length - i, 3); + const n: int = Math.min(digits.length - i, 3); bb.appendBits(parseInt(digits.substr(i, n), 10), n * 3 + 1); i += n; } @@ -827,8 +827,8 @@ namespace qrcodegen { // the given version. The result is infinity if a segment has too many characters to fit its length field. public static getTotalBits(segs: Array, version: int): number { let result: number = 0; - for (let seg of segs) { - let ccbits: int = seg.mode.numCharCountBits(version); + for (const seg of segs) { + const ccbits: int = seg.mode.numCharCountBits(version); if (seg.numChars >= (1 << ccbits)) return Infinity; // The segment's length doesn't fit the field's bit width result += 4 + ccbits + seg.bitData.length; @@ -922,8 +922,8 @@ namespace qrcodegen { public getRemainder(data: Array): Array { // Compute the remainder by performing polynomial division let result: Array = this.coefficients.map(_ => 0); - for (let b of data) { - let factor: byte = b ^ (result.shift() as int); + for (const b of data) { + const factor: byte = b ^ (result.shift() as int); result.push(0); for (let i = 0; i < result.length; i++) result[i] ^= ReedSolomonGenerator.multiply(this.coefficients[i], factor);